pith. sign in

arxiv: 2605.19874 · v2 · pith:HL2LE3L3new · submitted 2026-05-19 · ⚛️ physics.chem-ph

FNO-CCSDTQ(5)_Λ as an economical alternative for connected quintuple excitations contributions in coupled cluster thermochemistry

Pith reviewed 2026-05-22 09:30 UTC · model grok-4.3

classification ⚛️ physics.chem-ph
keywords coupled clusterquintuple excitationsfrozen natural orbitalsthermochemistrycorrelation energycomputational chemistry
0
0 comments X

The pith

Frozen natural orbital truncation makes connected quintuple excitations practical for coupled cluster thermochemistry.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

Contributions from connected quintuple excitations can reach 0.5 kcal/mol in thermochemical calculations, but the steep N^12 scaling prevents routine use. The paper tests whether a frozen natural orbital expansion converges rapidly enough for the differential quintuple contribution to support low-cost approximations. Calculations at natural orbital cutoffs of 0.0025 or 0.001 yield viable results, and a simple extrapolation from the pair 0.005 and 0.0025 performs well as an even cheaper option. Convergence is slower for second-row compounds than for first-row ones.

Core claim

We show that for the differential contribution of quintuples, convergence of a frozen natural orbital (FNO) expansion with respect to the NO cutoff is rapid enough to make FNO-CCSDTQ(5)Λ with cutoffs of 0.0025 or 0.001 viable alternatives. A naive extrapolation to zero cutoff from {0.005,0.0025} works surprisingly well as a low-cost option.

What carries the argument

Frozen natural orbital (FNO) truncation applied to the CCSDTQ(5)Λ method, selecting a subset of natural orbitals via occupation cutoff to approximate the connected quintuple excitation contributions.

If this is right

  • Quintuple corrections become feasible for larger first-row molecules in routine thermochemistry workflows.
  • The naive extrapolation provides a low-cost route to near-full accuracy for the quintuple term.
  • Second-row compounds require tighter cutoffs or additional checks because their FNO convergence is slower.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The same FNO approach could be tested on other high-order connected excitations beyond quintuples.
  • Integration with existing composite methods might further reduce overall computational cost in thermochemical databases.
  • Broader validation on systems with heavier elements could identify where tighter thresholds are mandatory.

Load-bearing premise

The chosen test set of molecules adequately represents convergence behavior for the differential quintuple contribution across first- and second-row compounds while keeping FNO truncation errors below the 0.5 kcal/mol target accuracy.

What would settle it

A direct comparison on a second-row molecule showing that the quintuple contribution at a 0.001 cutoff differs from the full calculation or extrapolated value by more than 0.5 kcal/mol would falsify the viability of these cutoffs.

Figures

Figures reproduced from arXiv: 2605.19874 by Aditya Barman, Gregory H. Jones, Jan M. L. Martin, Margarita Shepelenko.

Figure 1
Figure 1. Figure 1: FIG. 1. Natural orbital occupations of some isovalent species pairs [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. Natural orbital occupations of ozone with different basis [PITH_FULL_IMAGE:figures/full_fig_p005_2.png] view at source ↗
read the original abstract

Contributions from connected quintuple excitations in coupled cluster theory can reach the 0.5 kcal/mol range, important enough to matter in accurate computational thermochemistry, yet the very steep $\propto N^{12}$ CPU time scaling impedes routine evaluation. We show that for the differential contribution of quintuples, convergence of a frozen natural orbital (FNO) expansion with respect to the NO cutoff is rapid enough to make FNO-CCSDTQ(5)$_\Lambda$ with cutoffs of 0.0025 or 0.001 viable alternatives. A naive extrapolation to zero cutoff from \{0.005,0.0025\} works surprisingly well as a low-cost option. Interestingly, FNO convergence is definitely slower for second-row than for first-row compounds.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The manuscript proposes FNO-CCSDTQ(5)Λ as an economical alternative for approximating connected quintuple excitation contributions in coupled-cluster thermochemistry. It reports that the differential quintuple contribution converges rapidly with respect to the frozen natural orbital cutoff, rendering cutoffs of 0.0025 or 0.001 viable and a naive extrapolation from the set {0.005, 0.0025} surprisingly effective, while noting slower convergence for second-row compounds.

Significance. If the reported convergence rates and error magnitudes hold, the method would offer a practical route to include quintuple contributions at reduced cost while targeting 0.5 kcal/mol thermochemical accuracy. The work rests on standard CC theory and FNO truncation, with numerical tests rather than ad-hoc parameters; this is a strength. However, the significance is tempered by the need for broader test-set coverage and explicit bounds on truncation errors, especially for second-row species where slower convergence is acknowledged.

major comments (2)
  1. [Abstract] Abstract: The central claim that FNO cutoffs of 0.0025 or 0.001 keep truncation errors small enough not to compromise 0.5 kcal/mol accuracy requires explicit quantification of the maximum (not merely average) truncation error at these cutoffs across all tested molecules. The abstract flags slower convergence for second-row compounds, yet without tabulated maximum errors or a clear statement that the test set contains representative second-row cases, the generalization to the target accuracy remains unverified.
  2. [Results] Presumed Results section: The statement that naive extrapolation from {0.005, 0.0025} 'works surprisingly well' is load-bearing for the low-cost option claim. The manuscript should report the actual residuals of this extrapolation versus direct calculations at a smaller cutoff (e.g., 0.001) for each molecule or class, rather than qualitative description, to demonstrate that extrapolation residuals do not exceed the direct-cutoff errors.
minor comments (2)
  1. [Introduction] The notation CCSDTQ(5)Λ should be defined explicitly on first use, including the meaning of the subscript Λ, to aid readers outside the immediate CC community.
  2. Figure captions or a methods table should list the exact molecules in the test set, their row classification (first- vs. second-row), and the basis sets employed, to allow direct assessment of coverage.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive and detailed report. The comments highlight important points for strengthening the quantitative support of our claims regarding truncation errors and extrapolation performance. We address each major comment below and will incorporate the requested data into a revised manuscript.

read point-by-point responses
  1. Referee: [Abstract] Abstract: The central claim that FNO cutoffs of 0.0025 or 0.001 keep truncation errors small enough not to compromise 0.5 kcal/mol accuracy requires explicit quantification of the maximum (not merely average) truncation error at these cutoffs across all tested molecules. The abstract flags slower convergence for second-row compounds, yet without tabulated maximum errors or a clear statement that the test set contains representative second-row cases, the generalization to the target accuracy remains unverified.

    Authors: We agree that maximum truncation errors must be reported explicitly to substantiate the 0.5 kcal/mol accuracy target. In the revised manuscript we will add a table (or supplementary table) listing the maximum, mean, and standard deviation of the differential quintuple truncation errors at cutoffs 0.0025 and 0.001 for the full test set, with a separate breakdown for first-row versus second-row species. We will also add a sentence confirming that the test set includes representative second-row molecules (e.g., those containing S and Cl) and that the slower convergence for these species is already quantified in the results section. revision: yes

  2. Referee: [Results] Presumed Results section: The statement that naive extrapolation from {0.005, 0.0025} 'works surprisingly well' is load-bearing for the low-cost option claim. The manuscript should report the actual residuals of this extrapolation versus direct calculations at a smaller cutoff (e.g., 0.001) for each molecule or class, rather than qualitative description, to demonstrate that extrapolation residuals do not exceed the direct-cutoff errors.

    Authors: We accept that a qualitative statement is insufficient for a load-bearing claim. The revised manuscript will include a new table (or expanded results subsection) that reports, for every molecule, the absolute residual between the extrapolated value and the direct FNO-CCSDTQ(5)Λ result at cutoff 0.001. Results will be grouped by first-row and second-row compounds so that readers can directly compare extrapolation residuals to the corresponding direct-cutoff errors. revision: yes

Circularity Check

0 steps flagged

No significant circularity in FNO convergence demonstration for quintuple contributions

full rationale

The paper's central claim is supported by direct numerical computations showing rapid convergence of the FNO expansion for differential quintuple excitation contributions in CCSDTQ(5)Λ, with explicit results for cutoffs 0.0025/0.001 and a naive extrapolation. No equations or steps reduce the reported viability to a fitted parameter or self-definition by construction. The approach applies standard coupled-cluster theory and frozen natural orbital truncation, with convergence behavior tested on a molecular test set (including noted slower convergence for second-row species). No load-bearing self-citations, uniqueness theorems, or ansatzes imported from prior author work are invoked in the provided text. The derivation remains self-contained against external benchmarks of CC and FNO methods.

Axiom & Free-Parameter Ledger

1 free parameters · 2 axioms · 0 invented entities

The paper relies on standard coupled-cluster theory and the frozen-natural-orbital approximation; the only adjustable elements are the NO cutoff thresholds chosen after convergence tests.

free parameters (1)
  • NO cutoff threshold = 0.0025 or 0.001
    Values 0.005, 0.0025, and 0.001 are selected as practical points where convergence is judged sufficient; they are not derived from first principles.
axioms (2)
  • standard math Standard assumptions of coupled-cluster theory including the validity of the CCSDTQ(5) hierarchy for differential correlation contributions
    Invoked throughout the abstract when discussing quintuple contributions and their magnitude.
  • domain assumption Frozen natural orbitals provide a faithful truncation for the differential quintuple excitation energy
    Central premise that allows the cutoff-based approximation.

pith-pipeline@v0.9.0 · 5682 in / 1442 out tokens · 37354 ms · 2026-05-22T09:30:36.529379+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Lean theorems connected to this paper

Citations machine-checked in the Pith Canon. Every link opens the source theorem in the public Lean library.

What do these tags mean?
matches
The paper's claim is directly supported by a theorem in the formal canon.
supports
The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
extends
The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
uses
The paper appears to rely on the theorem as machinery.
contradicts
The paper's claim conflicts with a theorem or certificate in the canon.
unclear
Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.

Reference graph

Works this paper leans on

196 extracted references · 196 canonical work pages · 1 internal anchor

  1. [1]

    Journal of Computational Chemistry , year =

    Waigum, Alexander and Suchaneck, Sarah and Köhn, Andreas , title =. Journal of Computational Chemistry , year =

  2. [2]

    and Petersson, G

    Nyden, Marc R. and Petersson, G. A. , title =. 1981 , month =

  3. [3]

    and Mancini, John S

    Vu, Khanh and Pandian, Joshua and Zhang, Boyi and Annas, Christina and Parker, Anna J. and Mancini, John S. and Wang, Evan B. and Saldana-Greco, Diomedes and Nelson, Emily S. and Springsted, Greg and Lischka, Hans and Plasser, Felix and Parish, Carol A. , title =. 2024 , volume =

  4. [4]

    Economical Post-

    Amir Karton and Ilya Kaminker and Jan M L Martin , doi =. Economical Post-. 2009 , note =

  5. [6]

    Amir Karton and Jan M. L. Martin , doi =. W4 thermochemistry of

  6. [7]

    Joakim and Taylor, Peter R

    Persson, B. Joakim and Taylor, Peter R. and Lee, Timothy J. , title =. 1997 , volume =

  7. [8]

    , title =

    Papajak, Ewa and Truhlar, Donald G. , title =. 2011 , volume =

  8. [9]

    2015 , volume =

    Chan, Bun and Radom, Leo , title =. 2015 , volume =

  9. [10]

    and Zerzucha, Piotr and Kuś, Tomasz and Bartlett, Rodney J

    Musiał, Monika and Kucharski, Stanisław A. and Zerzucha, Piotr and Kuś, Tomasz and Bartlett, Rodney J. , title =. 2009 , volume =

  10. [11]

    2012 , volume =

    Daoling Peng and Markus Reiher , title =. 2012 , volume =. doi:10.1007/s00214-011-1081-y , url =

  11. [12]

    On the theoretical determination of the electron affinity of ozone , journal = tca, year =

    Gonz. On the theoretical determination of the electron affinity of ozone , journal = tca, year =

  12. [13]

    and Xu, Cangshan and Kim, Eun H

    Arnold, Don W. and Xu, Cangshan and Kim, Eun H. and Neumark, Daniel M. , title =. 1994 , volume =

  13. [14]

    and Engelking, Paul C

    Novick, Stewart E. and Engelking, Paul C. and Jones, Patrick L. and Futrell, Jean H. and Lineberger, W. Carl , title =. 1979 , volume =

  14. [15]

    Second-Order Perturbation Theory with a

    Andersson, Kerstin and Malmqvist, Per-. Second-Order Perturbation Theory with a. 1990 , volume =

  15. [16]

    Second-Order Perturbation Theory with a Complete Active Space Self-Consistent Field Reference Function , journal = jcp, year =

    Andersson, Kerstin and Malmqvist, Per-. Second-Order Perturbation Theory with a Complete Active Space Self-Consistent Field Reference Function , journal = jcp, year =

  16. [17]

    2004 , volume =

    Triplet instability in doublet systems , author =. 2004 , volume =. doi:10.1063/1.1795153 , url =

  17. [18]

    and Ornellas, Fernando R

    Denis, Pablo A. and Ornellas, Fernando R. , title =. Chemical Physics Letters , year =. doi:10.1016/j.cplett.2008.09.025 , url =

  18. [19]

    1992 , publisher =

    The coupled-cluster single, double, triple, and quadruple excitation method , author =. 1992 , publisher =

  19. [20]

    and Gauss, J

    Matthews, Devin A. and Gauss, J. Revisitation of Nonorthogonal Spin Adaptation in Coupled Cluster Theory , journal = jctc, year =

  20. [22]

    , title =

    Matthews, Devin A. , title =. SIAM Journal on Scientific Computing , volume =. 2018 , doi =

  21. [23]

    Maciej Spiegel and Emmanouil Semidalas and Jan M. L. Martin and Megan R. Bentley and John F. Stanton , doi =. Post-

  22. [24]

    Karton, Amir , doi =

  23. [25]

    Thorpe and David Feller and David H

    James H. Thorpe and David Feller and David H. Bross and Branko Ruscic and John F. Stanton , journal = pccp, year =. Sub 20 cm ^

  24. [26]

    Thorpe and Josie L

    James H. Thorpe and Josie L. Kilburn and David Feller and P. Bryan Changala and David H. Bross and Branko Ruscic and John F. Stanton , journal = jcp, year =. Elaborated thermochemical treatment of

  25. [27]

    Jones and Kaila E

    Aditya Barman and Gregory H. Jones and Kaila E. Weflen and Margarita Shepelenko and Jan M. L. Martin , year=. Coupling between thermochemical contributions of subvalence correlation and of higher-order post-

  26. [28]

    , title = "

    Goodson, David Z. , title = ". 2002 , month =. doi:10.1063/1.1462620 , url =

  27. [29]

    David , title =

    Sinnokrot, Mutasem Omar and Sherrill, C. David , title =. 2004 , doi =

  28. [30]

    Lesiuk, Michał , title =

  29. [31]

    Vladimir Fishman and Emmanouil Semidalas and Margarita Shepelenko and Jan M. L. Martin , title=. 2025 , pages=

  30. [32]

    2024 , eprint=

    Factorized Quadruples and a Predictor of Higher-Level Correlation in Thermochemistry , author=. 2024 , eprint=

  31. [33]

    Averting the Infrared Catastrophe in the Gold Standard of Quantum Chemistry , author =. Phys. Rev. Lett. , volume =. 2023 , month =

  32. [34]
  33. [35]

    and Valeev, Edward F

    Kong, Liguo and Bischoff, Florian A. and Valeev, Edward F. , doi =

  34. [36]

    Wiley Interdiscip

    Ten-no, Seiichiro and Noga, Jozef , doi =. Wiley Interdiscip. Rev. Comput. Mol. Sci. , month =

  35. [40]

    and Peterson, Kirk A

    Dunning Jr., Thom H. and Peterson, Kirk A. and Woon, David E. , city =. doi:10.1002/0470845015.cca053 , title =

  36. [41]

    and Dunning Jr., Thom H

    Kendall, Rick A. and Dunning Jr., Thom H. and Harrison, Robert J. , year =. Electron affinities of the first-row atoms revisited. Systematic basis sets and wave functions , volume =. doi:10.1063/1.462569 , number =

  37. [42]

    and Dunning Jr., Thom H

    Woon, David E. and Dunning Jr., Thom H. , doi =. Gaussian-Basis Sets for Use in Correlated Molecular Calculations .3

  38. [43]

    Comparison of

    Yuan He and Zhi He and Dieter Cremer , doi =. Comparison of. Theor. Chem. Acc. , keywords =

  39. [44]

    Bartlett and Miroslav Urban , doi =

    Jozef Noga and Rodney J. Bartlett and Miroslav Urban , doi =. Towards a full

  40. [45]

    Cole and Rodney J

    Miroslav Urban and Jozef Noga and Samuel J. Cole and Rodney J. Bartlett , doi =. Towards a full CCSDT model for electron correlation , volume =

  41. [46]

    1990 , doi =

    The coupled‐cluster single, double, and triple excitation model for open‐shell single reference functions , author=. 1990 , doi =

  42. [47]

    Air Force Office of Scientific Research

    Fifth-Order Many-Body Perturbation Theory and Its Relationship to Various Coupled-Cluster Approaches**This research has been supported by the U.S. Air Force Office of Scientific Research. , editor =. Adv. Quantum Chem. , publisher =. 1986 , issn =. doi:10.1016/S0065-3276(08)60051-9 , author =

  43. [48]

    2011 , publisher=

    S66: A well-balanced database of benchmark interaction energies relevant to biomolecular structures , author=. 2011 , publisher=

  44. [50]

    Stanton, John F , journal=ppl, volume=. Why. 1997 , publisher=

  45. [51]

    Daniel and Stanton, John F

    Crawford, T. Daniel and Stanton, John F. , doi =

  46. [54]

    Noga, Jozef and Bartlett, Rodney J. , doi =

  47. [56]

    Brauer, Brina and Kesharwani, Manoj Kumar and Kozuch, Sebastian and Martin, Jan M. L. , doi =

  48. [58]

    Francis and Bernardi, Fernando , doi =

    Boys, S. Francis and Bernardi, Fernando , doi =. Mol. Phys. , month =

  49. [59]

    Vladimir Fishman and Emmanouil Semidalas and Jan M. L. Martin , journal = jpca, keywords =. doi:10.1021/acs.jpca.4c03012 , title =

  50. [60]

    Szalay and Attila G

    Attila Tajti and Péter G. Szalay and Attila G. Császár and Mihály Kállay and Jürgen Gauss and Edward F. Valeev and Bradley A. Flowers and Juana Vázquez and John F. Stanton , doi =. HEAT: High accuracy extrapolated ab initio thermochemistry. , volume =

  51. [61]

    High-accuracy extrapolated ab initio thermochemistry

    Yannick J Bomble and Juana Vázquez and Mihály Kállay and Christine Michauk and Péter G Szalay and Attila G Császár and Jürgen Gauss and John F Stanton , doi =. High-accuracy extrapolated ab initio thermochemistry

  52. [62]

    Harding and Juana Vázquez and Branko Ruscic and Angela K

    Michael E. Harding and Juana Vázquez and Branko Ruscic and Angela K. Wilson and Jürgen Gauss and John F. Stanton , doi =. High-accuracy extrapolated ab initio thermochemistry

  53. [63]

    Thorpe and Chris A

    James H. Thorpe and Chris A. Lopez and T. Lam Nguyen and Joshua H. Baraban and David H. Bross and Branko Ruscic and John F. Stanton , doi =. High-accuracy extrapolated ab initio thermochemistry

  54. [64]

    and Dixon, D

    Feller, David and Peterson, Kirk A. and Dixon, D. A. , title =

  55. [67]

    2013 , month = apr, pages =

    Describing Noncovalent Interactions beyond the Common Approximations: How Accurate Is the `Gold Standard',. 2013 , month = apr, pages =. doi:10.1021/ct400057w , number =

  56. [69]

    and Cundari, Thomas R

    DeYonker, Nathan J. and Cundari, Thomas R. and Wilson, Angela K. , year =. The correlation consistent composite approach (ccCA): An alternative to the Gaussian-n methods , volume =. doi:10.1063/1.2173988 , number =

  57. [70]

    and Wilson, Angela K

    Peterson, Charles and Penchoff, Deborah A. and Wilson, Angela K. , editor =. 2016 , pages =. doi:10.1016/bs.arcc.2016.04.001 , publisher =

  58. [71]

    A coupled cluster approach with triple excitations

    Lee, Yoon S and Kucharski, Stanislaw A and Bartlett, Rodney J. A coupled cluster approach with triple excitations

  59. [72]

    Nagy and Mihály Kállay , title =

    Péter R. Nagy and Mihály Kállay , title =. 2019 , volume =

  60. [73]

    Nagy and Gyula Samu and Mih \'a ly K \'a llay

    P \'e ter R. Nagy and Gyula Samu and Mih \'a ly K \'a llay. Optimization of the linear-scaling local natural orbital CCSD(T) method: Improved algorithm and benchmark applications

  61. [74]

    P \'e ter R. Nagy. State-of-the-art local correlation methods enable accurate and affordable gold standard quantum chemistry up to a few hundred atoms. Chem. Sci

  62. [75]

    2016 , doi =

    Dubecký, Matúš and Mitas, Lubos and Jurečka, Petr , title =. 2016 , doi =

  63. [76]

    Canonical coupled cluster binding benchmark for nanoscale noncovalent complexes at the hundred-atom scale , volume =

    Lao, Ka Un , year =. Canonical coupled cluster binding benchmark for nanoscale noncovalent complexes at the hundred-atom scale , volume =. doi:10.1063/5.0242359 , number =

  64. [77]

    Interactions between large molecules pose a puzzle for reference quantum mechanical methods , author =. Nat. Commun. 2021 , doi =

  65. [78]

    Benchmark database of accurate (

    Jure. Benchmark database of accurate (. 2006 , doi=

  66. [79]

    2024 , eprint=

    Understanding Discrepancies of Wavefunction Theories for Large Molecules , author=. 2024 , eprint=

  67. [80]

    Petersson and David Feller and Kirk A

    Ericka C Barnes and George A. Petersson and David Feller and Kirk A. Peterson , doi =. The CCSD(T) complete basis set limit for Ne revisited. , volume =

  68. [81]

    J. Phys. Chem. , month =. doi:10.1021/j100103a020 , issn =

  69. [82]

    and Lao, Ka Un and Herbert, John M

    Richard, Ryan M. and Lao, Ka Un and Herbert, John M. , year =. Achieving the CCSD(T) Basis-Set Limit in Sizable Molecular Clusters: Counterpoise Corrections for the Many-Body Expansion , volume =. J. Phys. Chem. Lett. , publisher =. doi:10.1021/jz401368u , number =

  70. [83]
  71. [84]

    and Truhlar, Donald G

    Papajak, Ewa and Zheng, Jingjing and Xu, Xuefei and Leverentz, Hannah R. and Truhlar, Donald G. , doi =

  72. [85]

    Jan M. L. Martin and Peter R. Taylor , doi =. Benchmark quality total atomization energies of small polyatomic molecules , volume =

  73. [86]

    António J. C. Varandas , doi =. Canonical versus explicitly correlated coupled cluster: Post‐complete‐basis‐set extrapolation and the quest of the complete‐basis‐set limit , volume =

  74. [87]

    , journal=jcp, volume=

    Dunning Jr, Thom H. , journal=jcp, volume=. Gaussian basis sets for use in correlated molecular calculations. 1989 , publisher=

  75. [88]

    Hill, Robert Nyden , doi =

  76. [89]

    Schwartz, Charles , doi =. Phys. Rev. , month =

  77. [90]

    Kutzelnigg, Werner and Morgan, John D , doi =

  78. [91]

    Schwenke, David W. , doi =. Mol. Phys. , keywords =

  79. [92]

    and Silverstone, Harris J

    Carroll, Dennis P. and Silverstone, Harris J. and Metzger, Robert Melville , doi =

  80. [93]

    and Petersson, George A

    Ranasinghe, Duminda S. and Petersson, George A. , doi =

Showing first 80 references.