Pith. sign in

Paper Citation Record · LEDGER

Injectivity and the Law of Demand

As of 17 August 2026, this Paper Citation Record lists 37 of 37 outbound references and 0 inbound Pith citation observations for arXiv:1908.05714.

A citation records a reference. It does not transfer a finding from one paper to another.

pith.paper-citation-record.v1
1908.05714 v1

Coverage vector

measured 37 of 37 reference resolution

Typed states for the displayed outbound observations.

Source: paper_references, paper_reference_links, observed 2026-08-14T13:15:20.021647Z

measured 37 of 37 standing notices

One-hop event checks from named stored sources.

Source: scholarly_work_events, retraction_status_cache, observed 2026-08-17T06:30:58.91139+00:00

measured 0 of 0 inbound itemization

Pith citing papers itemized under the disclosed page cap.

Source: paper_references, paper_reference_links

measured 0 of 1 external citation measurements

A source-named dated measurement, never combined with another source.

Source: cited_works

Reference resolution

37 of 37 outbound references displayed

  • verified exact0
  • verified fuzzy36
  • unresolved1
  • parse uncertain0
  • malformed identifier0
  • metadata mismatch0

External citation measurements

No source-named external measurement is stored.

Outbound references

Observation 9303e9b0-5a0a-429d-bdad-a1a2e86287e5 · outbound

This paper cites Nonparametric counterfactual predictions in neoclassical models of international trade.

Injectivity and the Law of Demand Nonparametric counterfactual predictions in neoclassical models of international trade

Reference 1

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.584682Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.844100Z digest=sha256:47a28199730b5da65905dc3a6f688179242fb6d2a61efc5a00009799955aeef5

Observation 3584afe8-cd3f-470b-ab27-d6fb03052494 · outbound

This paper cites Demand analysis using strategic reports: An application to a school choice mechanism.

Injectivity and the Law of Demand Demand analysis using strategic reports: An application to a school choice mechanism

Reference 2

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.565328Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.849309Z digest=sha256:462f9d702fd92272da8ab8b0ce40d7a8dc352db386368e1ac9c15f3299dbff42

Observation 4d13a284-d1b1-4d0c-85c6-0002b95453cc · outbound

This paper cites Simple estimators for invertible index models.

Injectivity and the Law of Demand Simple estimators for invertible index models

Reference 3

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.547610Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.854671Z digest=sha256:b4f2b7aa22181694fdd3e7d11c943195bb431d08c5e5c3b54e64d95f069dcd13

Observation bed1b6bb-f210-45ed-8106-781d55494025 · outbound

This paper cites Identification with additively separable heterogeneity.

Injectivity and the Law of Demand Identification with additively separable heterogeneity

Reference 4

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.528331Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.859434Z digest=sha256:eb48233471ee574340cf3e232c519faf37824acfcebcf0da7095302103f53c40

Observation f54fec28-61e2-4535-bd5e-68b8a881ccb8 · outbound

This paper cites On the stability of the competitive equilibrium, i.

Injectivity and the Law of Demand On the stability of the competitive equilibrium, i

Reference 5

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.511950Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.864438Z digest=sha256:a7cd58ac21956461a9540b88cdbe4bc9f30f24009723bf57419fa1d254de2e08

Observation 5961986b-ee19-4961-87e2-38a5e2b5ec43 · outbound

This paper cites Some remarks on the equilibria of economic systems.

Injectivity and the Law of Demand Some remarks on the equilibria of economic systems

Reference 6

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.497816Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.870394Z digest=sha256:b7630b254d3501ca56b8fba47e2f89d042bf904252125cf79ca757478d9fb216

Observation c03d62dd-0be0-4973-87fa-01e895cfaa07 · outbound

This paper cites Walrasian equilibrium in large, quasilinear markets.

Injectivity and the Law of Demand Walrasian equilibrium in large, quasilinear markets

Reference 7

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.485668Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.875751Z digest=sha256:ea7aaeda8999360bf1697c6468af63aeb96b1caed144819668a9d423eb1c9515

Observation 67577442-8dc1-4aa5-88b2-5358af57d137 · outbound

This paper cites Heterogeneity and the non-parametric analysis of consumer choice: conditions for invertibility.

Injectivity and the Law of Demand Heterogeneity and the non-parametric analysis of consumer choice: conditions for invertibility

Reference 8

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.472063Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.880147Z digest=sha256:afb5f0426f481ac857eb6989ebfa5490a124d288c65f8fad3b617580a2c3b590

Observation 408597f5-a2d7-49c2-b821-b27aebbff2c3 · outbound

This paper cites Automobile prices in market equilibrium.

Injectivity and the Law of Demand Automobile prices in market equilibrium

Reference 9

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.456166Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.884555Z digest=sha256:4276ceda7f0d57b5f56c14b89cbee1853cc4c6a121315a67cfc2f83c26e8ffde

Observation 5624a661-c1d5-47be-bba7-9a88494f4196 · outbound

This paper cites Connected substitutes and invertibility of demand.

Injectivity and the Law of Demand Connected substitutes and invertibility of demand

Reference 10

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.442954Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.888882Z digest=sha256:51478ae14c2853216c838704a210bcc9d3151bda5ad55c965eee74624ffc7030

Observation 2f104880-71a6-4a7f-8a16-0e26ba1242d4 · outbound

This paper cites Estimating discrete-choice models of product differentiation.

Injectivity and the Law of Demand Estimating discrete-choice models of product differentiation

Reference 11

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.426675Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.893716Z digest=sha256:9e9469966f8aec54871544790551c928a0a6a133db730ea5c28330cdbaedc74d

Observation b6ea2830-ee44-4b97-b350-ddde2d878a0d · outbound

This paper cites Nonparametric identification of multinomial choice demand models with heterogeneous consumers.

Injectivity and the Law of Demand Nonparametric identification of multinomial choice demand models with heterogeneous consumers

Reference 12

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.406368Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.898953Z digest=sha256:941a6b5ffb67fb72dea6e73b3196632954d8b12f80ef756c209ab2deca4710fd

Observation 84d9319b-88ed-48d1-9747-8cde78332388 · outbound

This paper cites Identification in differentiated products markets using market level data.

Injectivity and the Law of Demand Identification in differentiated products markets using market level data

Reference 13

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.391421Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.903817Z digest=sha256:cc180882bbfc23e0e93df2eb6e522346c15314759141ef4b4b58d4166ccd90da

Observation 354e5cfc-64ff-4d6d-a035-3bf33d7fa393 · outbound

This paper cites Identification of nonparametric simultaneous equations models with a residual index structure.

Injectivity and the Law of Demand Identification of nonparametric simultaneous equations models with a residual index structure

Reference 14

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.377292Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.911104Z digest=sha256:e09354c5605c6c77623d8a047963ae24c2eba48a0528f87f29e2c778c025c0a5

Observation 09857adc-f40f-44d4-8994-f21b5e50d1f3 · outbound

This paper cites Individual counterfactuals with multidimensional unobserved heterogeneity.

Injectivity and the Law of Demand Individual counterfactuals with multidimensional unobserved heterogeneity

Reference 15

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.364107Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.918627Z digest=sha256:66aac7d3050629da89df416d0efaad83f53e1cf5ed5b0448c0c13446532aa845

Observation 8e6a4747-d654-4519-9df9-313aff0396bb · outbound

This paper cites Yogurts choose consumers? identification of random utility models via two-sided matching.

Injectivity and the Law of Demand Yogurts choose consumers? identification of random utility models via two-sided matching

Reference 16

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.351702Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.925450Z digest=sha256:69e4c2fd74a4ad695f0cb4055c32eddabb87227ff2505b0fa2be0155c48ff528

Observation fad25524-baec-4e18-a68d-3a282c6f1624 · outbound

This paper cites The nonparametric approach to applied welfare analysis.

Injectivity and the Law of Demand The nonparametric approach to applied welfare analysis

Reference 17

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.338671Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.931823Z digest=sha256:f3a0f0f62d4e105fcb43fd6438d0bb6999169e898cf43a1437561aeb79735416

Observation 994f7d13-5c93-4021-a21d-6edc79e03e86 · outbound

This paper cites Estimation of nonparametric functions in simultaneous equations models, with an application to consumer demand.

Injectivity and the Law of Demand Estimation of nonparametric functions in simultaneous equations models, with an application to consumer demand

Reference 18

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.324608Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.937295Z digest=sha256:1bbd0cc836cadaf42e0bc2b41adda95e7c6ac644feab20c08525215c8de4ff98

Observation 4269fbbc-88cf-4655-a1d5-b9aebd73cab0 · outbound

This paper cites Generalized instrumental variable models.

Injectivity and the Law of Demand Generalized instrumental variable models

Reference 19

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.311350Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.944451Z digest=sha256:0006096583b13b5b68dd42cc08edd5f97c2e03b6656560acca0baf66ab03a705

Observation 30bb2194-74f1-4d0d-9758-a83b3effa059 · outbound

This paper cites On the nonparametric identification of multiple choice models.

Injectivity and the Law of Demand On the nonparametric identification of multiple choice models

Reference 20

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.299129Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.948878Z digest=sha256:e7515e1219e2308542f62bb04e624c045a6a3cf1055fc7caac0e6203de731d6c

Observation 3fbdc02e-1fba-44ff-95d4-695cb49e375b · outbound

This paper cites Demand models for differentiated products with complementarity and substitutability.

Injectivity and the Law of Demand Demand models for differentiated products with complementarity and substitutability

Reference 21

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.285444Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.954236Z digest=sha256:3d46568ea4be352153be4291593ab6920580af081efed77ce362842326e83f48

Observation 0531c8b5-ec84-4dc6-ba07-80251bdd3cc6 · outbound

This paper cites Unobserved heterogeneity in matching games.

Injectivity and the Law of Demand Unobserved heterogeneity in matching games

Reference 22

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.270250Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.960062Z digest=sha256:c7670b6730581ec693929e181801b4ed8b94bfeb766cb1ec8ba59d4f2074b05f

Observation 4c76e551-9bfb-448e-9b77-cfe83a7d58d9 · outbound

This paper cites The jacobian matrix and global univalence of mappings.

Injectivity and the Law of Demand The jacobian matrix and global univalence of mappings

Reference 23

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.255727Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.964369Z digest=sha256:e92102eeff35b5ec9d3f009516d665d3e48af59ffb1202b5ed569d14977dc658

Observation 3659b181-a94c-4ade-b21d-6df0a16ab610 · outbound

This paper cites Valuing new goods in a model with complementarity: Online newspapers.

Injectivity and the Law of Demand Valuing new goods in a model with complementarity: Online newspapers

Reference 24

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.240795Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.968237Z digest=sha256:353eb5bd91adc67f3535027c15d06563db7ae2750623db4bd643a785947f1c51

Observation fef1eea3-6c2f-4f14-9598-9c98ac73b55d · outbound

This paper cites law of demand.

Injectivity and the Law of Demand law of demand

Reference 25

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.227221Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.972939Z digest=sha256:1a1d6aafa44a16541c4e1dd2675346b081fc477e6bb54ed4d1a51bf9134722d0

Observation 2c459a91-e3c2-4f38-aea7-d2c4ea45a529 · outbound

This paper cites On convexity of preimages of monotone operators.

Injectivity and the Law of Demand On convexity of preimages of monotone operators

Reference 26

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.213095Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.977230Z digest=sha256:bba65d4391f2927be08e7004148f60aa777840f98d8c5ae23d64cc98ac597f56

Observation 270d81f9-6106-4624-b950-3fb97ed392d8 · outbound

This paper cites On injectivity of a class of monotone operators with some univalency consequences.

Injectivity and the Law of Demand On injectivity of a class of monotone operators with some univalency consequences

Reference 27

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.196840Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.981052Z digest=sha256:01ae8dce34130823c99b5a2f72b4688dc12a561ec04bbb65385633b1d7b24e38

Observation a1b28777-635e-48e9-be12-44eb89526090 · outbound

This paper cites On the uniqueness of equilibrium once again.

Injectivity and the Law of Demand On the uniqueness of equilibrium once again

Reference 28

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.183364Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.984356Z digest=sha256:6a38f1dede50172b6fedc9f892f8c7a3355a7bb7ab4d8e8c3f42f59fac8064a8

Observation 180bcbdc-a923-4f07-9631-a7f754d21c8e · outbound

This paper cites Identification in nonparametric simultaneous equations models.

Injectivity and the Law of Demand Identification in nonparametric simultaneous equations models

Reference 29

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.169192Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.988191Z digest=sha256:db00e210484461192351075def7fc9b3f232a56eb3a90d33ddff137986516ee7

Observation a0cef305-c545-485f-a0bf-b94023f5539b · outbound

This paper cites Estimation of nonparametric models with simultaneity.

Injectivity and the Law of Demand Estimation of nonparametric models with simultaneity

Reference 30

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.155548Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.992044Z digest=sha256:8d06f14105f4997fa48aba693660806f2e23d26027e33fff8f5598e89d69f2e5

Observation cb58ded1-678e-4883-9211-511d6cee75d3 · outbound

This paper cites Econometric models of probabilistic choice.

Injectivity and the Law of Demand Econometric models of probabilistic choice

Reference 31

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.141051Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.995842Z digest=sha256:5a778359699ba999624deae4af30068adc2ab63f5e2ecf20a72e249b36bc3bc1

Observation 555836c8-59b7-458c-83a2-d019dea9bae1 · outbound

This paper cites On p-and s-functions and related classes of n-dimensional nonlinear mappings.

Injectivity and the Law of Demand On p-and s-functions and related classes of n-dimensional nonlinear mappings

Reference 32

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.127001Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:19.999890Z digest=sha256:8d94ea0918a860228b8d899c26769f6047e45c0121eef78d43dbb904350d1da6

Observation 0a1ee4b5-687f-4643-b009-b1fe87284c5a · outbound

This paper cites On the surjectivity of the mapping between utilities and choice probabilities.

Injectivity and the Law of Demand On the surjectivity of the mapping between utilities and choice probabilities

Reference 33

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.111346Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:20.004018Z digest=sha256:bf3ab34202c993a6532f2b919c3242b5d2d8c02932da8414621544a2d0a09fda

Observation bbf8f965-be54-4d26-91df-06aa9dee80b5 · outbound

This paper cites On global univalence theorems, volume 977 of Lecture Notes in Mathematics.

Injectivity and the Law of Demand On global univalence theorems, volume 977 of Lecture Notes in Mathematics

Reference 34

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.098308Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:20.007758Z digest=sha256:bdabb71fa9ec782ef9e1c170f760af6c3b27feed46752f9c6cf0e3f2ec02821f

Observation f4225870-8782-4d09-8b99-61e0fb895f4c · outbound

This paper cites Convex Analysis.

Injectivity and the Law of Demand Convex Analysis

Reference 35

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.084852Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:20.012176Z digest=sha256:3028b65dc983b320b570fc0693ee5e8f77f40fb0ef623fc8caf166b63ce596e1

Observation 4f906b31-28e2-4421-9a75-c766abf094ef · outbound

This paper cites Variational analysis, volume 317.

Injectivity and the Law of Demand Variational analysis, volume 317

Reference 36

Resolution
unresolved
no resolver link, observed 2026-08-14T13:15:20.016039Z

Source-reported events for the cited work

Unavailable: canonical work link unavailable.

source=arxiv_source observed=2026-08-14T13:15:20.016039Z digest=sha256:d7c51481b75825cab3ac00a06191c9130c7e6695a386ed6640e456a84a8b23b6

Observation fdb053bb-531f-4343-bd53-98751525760a · outbound

This paper cites Estimating semi-parametric panel multinomial choice models using cyclic monotonicity.

Injectivity and the Law of Demand Estimating semi-parametric panel multinomial choice models using cyclic monotonicity

Reference 37

Resolution
verified fuzzy
raw_fallback, observed 2026-08-14T13:15:20.062161Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-17T06:30:58.91139+00:00.

source=arxiv_source observed=2026-08-14T13:15:20.021647Z digest=sha256:d2947c4d802a1b3df060c0ebaec7837ba4fda86673c83d789d1872b2baed56d7

Pith citing papers

No inbound Pith citation observations are available.