Paper Citation Record · LEDGER

Inequivalent complexity criteria for free boundary minimal surfaces

As of 23 August 2026, this Paper Citation Record lists 52 of 52 outbound references and 0 inbound Pith citation observations for arXiv:1908.04709.

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

pith.paper-citation-record.v1
1908.04709 v3

Coverage vector

measured 52 of 52 reference resolution

Typed states for the displayed outbound observations.

Source: paper_references, paper_reference_links, observed 2026-08-14T13:41:49.833215Z

measured 52 of 52 standing notices

One-hop event checks from named stored sources.

Source: scholarly_work_events, retraction_status_cache, observed 2026-08-23T06:30:58.430688+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

52 of 52 outbound references displayed

verified exact4
verified fuzzy30
unresolved18
parse uncertain0
malformed identifier0
metadata mismatch0

External citation measurements

No source-named external measurement is stored.

Outbound references

Observation d9cc6034-3589-481d-8aa4-dd2697b0f0f9 · outbound

This paper cites an unresolved cited work.

Inequivalent complexity criteria for free boundary minimal surfaces Unresolved cited work

Reference 1

Resolution: unresolved; no resolver link, observed 2026-08-14T13:41:49.575659Z

Source-reported events for the cited work

Unavailable: canonical work link unavailable.

Observation bb6cb6d8-969a-4b93-bc31-476ca13687bb · outbound

This paper cites Ambrosio, A.

Inequivalent complexity criteria for free boundary minimal surfaces Ambrosio, A

Reference 2

Resolution: unresolved; no resolver link, observed 2026-08-14T13:41:49.581198Z

Source-reported events for the cited work

Unavailable: canonical work link unavailable.

Observation aa5e62c3-df6e-4dbb-bc0b-8f7ca60160e6 · outbound

This paper cites Ambrozio, R.

Inequivalent complexity criteria for free boundary minimal surfaces Ambrozio, R

Reference 3

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.692054Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 0d696201-eef7-4921-9c26-699d5e1060f1 · outbound

This paper cites Ambrozio, A.

Inequivalent complexity criteria for free boundary minimal surfaces Ambrozio, A

Reference 4

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.675434Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 9d6c5597-23c1-4477-9dd0-be146f613c9a · outbound

This paper cites an unresolved cited work.

Inequivalent complexity criteria for free boundary minimal surfaces Unresolved cited work

Reference 5

Resolution: unresolved; raw_fallback, observed 2026-08-14T13:41:50.659401Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 716c29a9-11cf-488d-8192-e30453fee317 · outbound

This paper cites Calabi, Minimal immersions of surfaces in Euclidean spheres , J.

Inequivalent complexity criteria for free boundary minimal surfaces Calabi, Minimal immersions of surfaces in Euclidean spheres , J

Reference 6

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.644127Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation b1d03e69-6779-46fc-ae45-472ebe44d25f · outbound

This paper cites Carlotto, Generic ﬁniteness of minimal surfaces with bounded Morse in dex, Ann.

Inequivalent complexity criteria for free boundary minimal surfaces Carlotto, Generic ﬁniteness of minimal surfaces with bounded Morse in dex, Ann

Reference 7

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.627701Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 2fe3129b-2f33-4deb-8581-6a936f6081eb · outbound

This paper cites Carlotto, O.

Inequivalent complexity criteria for free boundary minimal surfaces Carlotto, O

Reference 8

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.610925Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 176f89aa-90b8-46fb-a3b8-22686b4d0763 · outbound

This paper cites Constrained deformations of positive scalar curvature metrics.

Inequivalent complexity criteria for free boundary minimal surfaces Constrained deformations of positive scalar curvature metrics

Reference 9

Resolution: verified exact; local_arxiv, observed 2026-08-14T13:41:50.066654Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 1be872fc-7968-430d-a741-0397206b8714 · outbound

This paper cites Chodosh, D.

Inequivalent complexity criteria for free boundary minimal surfaces Chodosh, D

Reference 10

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.593620Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation aac15309-77a6-4ea4-a434-5771ce7afe9a · outbound

This paper cites Chodosh and D.

Inequivalent complexity criteria for free boundary minimal surfaces Chodosh and D

Reference 11

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.577630Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation dda22ed3-f634-4a6d-a763-f8a7b4e2dd60 · outbound

This paper cites On the topology and index of minimal surfaces II.

Inequivalent complexity criteria for free boundary minimal surfaces On the topology and index of minimal surfaces II

Reference 12

Resolution: verified exact; local_arxiv, observed 2026-08-14T13:41:50.043135Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 3b1d99aa-16d9-47f7-b7ae-2245eea58938 · outbound

This paper cites an unresolved cited work.

Inequivalent complexity criteria for free boundary minimal surfaces Unresolved cited work

Reference 13

Resolution: unresolved; raw_fallback, observed 2026-08-14T13:41:50.561571Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation a8776393-9201-4c8e-8c49-9a9786cafa42 · outbound

This paper cites Colding and C.

Inequivalent complexity criteria for free boundary minimal surfaces Colding and C

Reference 14

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.545632Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 0dc43b01-6552-4d36-8db8-b224f2726bc0 · outbound

This paper cites an unresolved cited work.

Inequivalent complexity criteria for free boundary minimal surfaces Unresolved cited work

Reference 15

Resolution: unresolved; raw_fallback, observed 2026-08-14T13:41:50.530044Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 43944718-348f-4b56-88d1-81dfe5424c8c · outbound

This paper cites 121, Amer.

Inequivalent complexity criteria for free boundary minimal surfaces 121, Amer

Reference 16

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.514730Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation ded49451-82b2-46b5-8c5f-49de28cf6091 · outbound

This paper cites Ejiri and M.

Inequivalent complexity criteria for free boundary minimal surfaces Ejiri and M

Reference 17

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.499557Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation a68fdf29-f9a2-493d-89c6-465535f37cbf · outbound

This paper cites Fischer-Colbrie, On complete minimal surfaces with ﬁnite Morse index in three -manifolds, Invent.

Inequivalent complexity criteria for free boundary minimal surfaces Fischer-Colbrie, On complete minimal surfaces with ﬁnite Morse index in three -manifolds, Invent

Reference 18

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.481159Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation bf097dc5-cbad-4642-9d04-d2d6d9f245e1 · outbound

This paper cites Fischer-Colbrie and R.

Inequivalent complexity criteria for free boundary minimal surfaces Fischer-Colbrie and R

Reference 19

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.464093Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 3810f0d3-d3a2-4fc5-a07d-6405f6662374 · outbound

This paper cites Fraser and M.

Inequivalent complexity criteria for free boundary minimal surfaces Fraser and M

Reference 20

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.446772Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 6da62404-d718-4f18-89f4-030fe80ac100 · outbound

This paper cites Fraser and R.

Inequivalent complexity criteria for free boundary minimal surfaces Fraser and R

Reference 21

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.430653Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 98848327-522d-40f5-b5bb-cbc23b8a4b56 · outbound

This paper cites Math., 5 99, Amer.

Inequivalent complexity criteria for free boundary minimal surfaces Math., 5 99, Amer

Reference 22

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.412801Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation d686c898-b7e1-4a62-9584-a20e961d85a8 · outbound

This paper cites an unresolved cited work.

Inequivalent complexity criteria for free boundary minimal surfaces Unresolved cited work

Reference 23

Resolution: unresolved; raw_fallback, observed 2026-08-14T13:41:50.395221Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation a05f233c-595c-4b59-800a-f1f7355ea1e6 · outbound

This paper cites Gromov and H.

Inequivalent complexity criteria for free boundary minimal surfaces Gromov and H

Reference 24

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.377490Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 96e53546-98ae-462a-a42e-edb147d73cc4 · outbound

This paper cites Min-max theory for free boundary minimal hypersurfaces II -- General Morse index bounds and applications.

Inequivalent complexity criteria for free boundary minimal surfaces Min-max theory for free boundary minimal hypersurfaces II -- General Morse index bounds and applications

Reference 25

Resolution: unresolved; no resolver link, observed 2026-08-14T13:41:49.695590Z

Source-reported events for the cited work

Unavailable: canonical work link unavailable.

Observation 80f82b64-17fd-4d49-8f6b-c571e8a7b07f · outbound

This paper cites Guang, M.

Inequivalent complexity criteria for free boundary minimal surfaces Guang, M

Reference 26

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.361452Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 7e89bfa3-acf8-4cf8-8f62-e58e5be55956 · outbound

This paper cites Compactness and generic finiteness for free boundary minimal hypersurfaces (I).

Inequivalent complexity criteria for free boundary minimal surfaces Compactness and generic finiteness for free boundary minimal hypersurfaces (I)

Reference 27

Resolution: unresolved; no resolver link, observed 2026-08-14T13:41:49.707144Z

Source-reported events for the cited work

Unavailable: canonical work link unavailable.

Observation 649f0fb0-f021-49e2-82c2-960e54b46875 · outbound

This paper cites Gulliver and H.

Inequivalent complexity criteria for free boundary minimal surfaces Gulliver and H

Reference 28

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.345328Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation a7368348-385e-487b-b7db-1b4bd05456ec · outbound

This paper cites Hartman, Geodesic parallel coordinates in the large , Amer.

Inequivalent complexity criteria for free boundary minimal surfaces Hartman, Geodesic parallel coordinates in the large , Amer

Reference 29

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.329336Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation e12688f3-bfdc-425d-b282-d9f0ffb890ef · outbound

This paper cites an unresolved cited work.

Inequivalent complexity criteria for free boundary minimal surfaces Unresolved cited work

Reference 30

Resolution: unresolved; raw_fallback, observed 2026-08-14T13:41:50.313237Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation bf5f0d07-bd2c-47a1-96ab-858b49f9eee8 · outbound

This paper cites Hsiang, Minimal cones and the spherical Bernstein problem.

Inequivalent complexity criteria for free boundary minimal surfaces Hsiang, Minimal cones and the spherical Bernstein problem

Reference 31

Resolution: unresolved; no resolver link, observed 2026-08-14T13:41:49.727235Z

Source-reported events for the cited work

Unavailable: canonical work link unavailable.

Observation 891a9456-ab97-49f1-900b-076bb478060f · outbound

This paper cites an unresolved cited work.

Inequivalent complexity criteria for free boundary minimal surfaces Unresolved cited work

Reference 32

Resolution: unresolved; raw_fallback, observed 2026-08-14T13:41:50.285229Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 132dc2d6-cb83-4c5a-ad12-fff000e30b74 · outbound

This paper cites Free Boundary Minimal Surfaces in the Unit Three-Ball via Desingularization of the Critical Catenoid and the Equatorial Disk.

Inequivalent complexity criteria for free boundary minimal surfaces Free Boundary Minimal Surfaces in the Unit Three-Ball via Desingularization of the Critical Catenoid and the Equatorial Disk

Reference 33

Resolution: verified exact; local_arxiv, observed 2026-08-14T13:41:49.985903Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 993c3efc-05fb-40e7-a09d-9e5fe09090c7 · outbound

This paper cites Free-boundary minimal surfaces with connected boundary in the $3$-ball by tripling the equatorial disc.

Inequivalent complexity criteria for free boundary minimal surfaces Free-boundary minimal surfaces with connected boundary in the $3$-ball by tripling the equatorial disc

Reference 34

Resolution: unresolved; no resolver link, observed 2026-08-14T13:41:49.743009Z

Source-reported events for the cited work

Unavailable: canonical work link unavailable.

Observation 0d73166e-696c-499c-b8ac-78075adb8cd7 · outbound

This paper cites Equivariant min-max theory.

Inequivalent complexity criteria for free boundary minimal surfaces Equivariant min-max theory

Reference 35

Resolution: unresolved; no resolver link, observed 2026-08-14T13:41:49.748328Z

Source-reported events for the cited work

Unavailable: canonical work link unavailable.

Observation fc9c4d9d-f5cc-48b6-b370-770ef51c97e4 · outbound

This paper cites Free boundary minimal surfaces of unbounded genus.

Inequivalent complexity criteria for free boundary minimal surfaces Free boundary minimal surfaces of unbounded genus

Reference 36

Resolution: unresolved; no resolver link, observed 2026-08-14T13:41:49.754148Z

Source-reported events for the cited work

Unavailable: canonical work link unavailable.

Observation f172e2b5-74c2-4adc-a7b9-8575a7b29476 · outbound

This paper cites Free boundary minimal surfaces in the unit ball : recent advances and open questions.

Inequivalent complexity criteria for free boundary minimal surfaces Free boundary minimal surfaces in the unit ball : recent advances and open questions

Reference 37

Resolution: unresolved; no resolver link, observed 2026-08-14T13:41:49.759272Z

Source-reported events for the cited work

Unavailable: canonical work link unavailable.

Observation b0bbdb57-e4cc-468b-94f1-f484dc98ad84 · outbound

This paper cites Li and X.

Inequivalent complexity criteria for free boundary minimal surfaces Li and X

Reference 38

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.270343Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation c593b5fc-f88e-4d94-9dd0-6650bca0ee99 · outbound

This paper cites Bounds for the Morse index of free boundary minimal surfaces.

Inequivalent complexity criteria for free boundary minimal surfaces Bounds for the Morse index of free boundary minimal surfaces

Reference 39

Resolution: verified exact; local_arxiv, observed 2026-08-14T13:41:49.895370Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 4f6383bd-8560-4ef1-9edf-251d629f07f8 · outbound

This paper cites an unresolved cited work.

Inequivalent complexity criteria for free boundary minimal surfaces Unresolved cited work

Reference 40

Resolution: unresolved; raw_fallback, observed 2026-08-14T13:41:50.255375Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation cdc0742e-0ef3-4909-baf9-d6c0339396ba · outbound

This paper cites Miao, Positive mass theorem on manifolds admitting corners along a hypersurface, Adv.

Inequivalent complexity criteria for free boundary minimal surfaces Miao, Positive mass theorem on manifolds admitting corners along a hypersurface, Adv

Reference 41

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.240641Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation e93f18b5-8185-4d0c-a0a3-01c3e808e6ae · outbound

This paper cites Schoen, Estimates for stable minimal surfaces in three dimensional manifolds, Seminar on minimal submanifolds, 111–126, Ann.

Inequivalent complexity criteria for free boundary minimal surfaces Schoen, Estimates for stable minimal surfaces in three dimensional manifolds, Seminar on minimal submanifolds, 111–126, Ann

Reference 42

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.225277Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation b4a3bd53-b9f0-4037-9508-781a6c906fa7 · outbound

This paper cites Diﬀerential Geom.

Inequivalent complexity criteria for free boundary minimal surfaces Diﬀerential Geom

Reference 43

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.209591Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 8d85d887-fcb3-46d9-a3e0-4190078f9f75 · outbound

This paper cites Schoen and L.

Inequivalent complexity criteria for free boundary minimal surfaces Schoen and L

Reference 44

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.194417Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 4b7c2169-8f2e-4acb-8c3d-fd028f2206bc · outbound

This paper cites Schoen and S.-T.

Inequivalent complexity criteria for free boundary minimal surfaces Schoen and S.-T

Reference 45

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.178794Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation e0fcbb28-55e9-4ebc-8e77-c67a654bc411 · outbound

This paper cites Positive Scalar Curvature and Minimal Hypersurface Singularities.

Inequivalent complexity criteria for free boundary minimal surfaces Positive Scalar Curvature and Minimal Hypersurface Singularities

Reference 46

Resolution: unresolved; no resolver link, observed 2026-08-14T13:41:49.804259Z

Source-reported events for the cited work

Unavailable: canonical work link unavailable.

Observation da6505c9-b638-489f-b57e-da0621eef05f · outbound

This paper cites Shiohama, T.

Inequivalent complexity criteria for free boundary minimal surfaces Shiohama, T

Reference 47

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.164206Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 0b6efb26-ead1-4ff7-a6fe-e44265ea097b · outbound

This paper cites Volkmann, Free boundary problems governed by mean curvature , Ph.D.

Inequivalent complexity criteria for free boundary minimal surfaces Volkmann, Free boundary problems governed by mean curvature , Ph.D

Reference 48

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.147868Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 89558d23-7392-46de-a68e-898eae8a0a13 · outbound

This paper cites White, Complete surfaces of ﬁnite total curvature , J.

Inequivalent complexity criteria for free boundary minimal surfaces White, Complete surfaces of ﬁnite total curvature , J

Reference 49

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.131495Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 8242744b-abed-46f8-9657-c18c3f56ae96 · outbound

This paper cites an unresolved cited work.

Inequivalent complexity criteria for free boundary minimal surfaces Unresolved cited work

Reference 50

Resolution: unresolved; raw_fallback, observed 2026-08-14T13:41:50.114977Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation ddd7799a-4553-4407-ae79-4e71729ef0f0 · outbound

This paper cites Diﬀerential Geom.

Inequivalent complexity criteria for free boundary minimal surfaces Diﬀerential Geom

Reference 51

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.098209Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Observation 01047623-20ae-42eb-8a91-51919c16328b · outbound

This paper cites Ser., 22 , Amer.

Inequivalent complexity criteria for free boundary minimal surfaces Ser., 22 , Amer

Reference 52

Resolution: verified fuzzy; raw_fallback, observed 2026-08-14T13:41:50.082460Z

Source-reported events for the cited work

No event found in the named queried sources as of 2026-08-23T06:30:58.430688+00:00.

Pith citing papers

No inbound Pith citation observations are available.