Typed states for the displayed outbound observations.
Source: paper_references, paper_reference_links, observed 2026-08-14T15:22:41.622758Z
Paper Citation Record · LEDGER
As of 14 August 2026, this Paper Citation Record lists 53 of 53 outbound references and 0 inbound Pith citation observations for arXiv:1908.01335.
A citation records a reference. It does not transfer a finding from one paper to another.
Typed states for the displayed outbound observations.
Source: paper_references, paper_reference_links, observed 2026-08-14T15:22:41.622758Z
One-hop event checks from named stored sources.
Source: scholarly_work_events, retraction_status_cache, observed 2026-08-14T06:32:32.682623+00:00
Pith citing papers itemized under the disclosed page cap.
Source: paper_references, paper_reference_links
A source-named dated measurement, never combined with another source.
Source: cited_works
53 of 53 outbound references displayed
External citation measurements
No source-named external measurement is stored.
Observation d305fcb1-66e5-40d7-b0fe-8ecb644db77b · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Cosmic Modesty
Reference 1
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation 4b2a89b2-f400-4667-b616-8d3e10e02aa5 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Sagan, The cosmic connection, (Anchor Press, 1973)
Reference 2
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation 30f670b8-2bc8-4cd9-bf10-28b42d08c133 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Unresolved cited work
Reference 3
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation 60aa0e7b-c728-4110-82d0-921710836c4c · outbound
Upper limit on the fraction of alien civilizations that develop communication technology A joint analysis of the Drake equation and the Fermi paradox
Reference 4
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation 270c7880-bd93-410d-b9c3-99101bbb7de9 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Is there anybody out there?
Reference 5
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation bb816c1e-d6be-4c66-b28f-3e307e088d50 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Albedos, Equilibrium Temperatures, and Surface Temperatures of Habitable Planets
Reference 6
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 158546ba-0f9a-4512-8b25-687ca33efbbb · outbound
Upper limit on the fraction of alien civilizations that develop communication technology On the Habitability of Our Universe
Reference 7
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation e3dd01b4-d58a-48ca-a6bb-c2c4c3b2bb06 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Seager, Exoplanet habitability, Science, 340, 577 (2013) doi: 10.1126/science.1232226
Reference 8
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation bc33eb49-3768-44da-9242-a275ea9bcc09 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Unresolved cited work
Reference 9
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation e7b1e30a-02f0-440b-b0ca-50c7962160a4 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Characteristics of planetary candidates observed by Kepler, II: Analysis of the first four months of data
Reference 10
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 533a9fd4-168a-42d1-a672-8049b59623a3 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Planetary Candidates Observed by Kepler, III: Analysis of the First 16 Months of Data
Reference 11
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 061b1844-209f-41d0-9527-93e5b31c3d77 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology The Occurrence Rate of Small Planets around Small Stars
Reference 12
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 41812b75-52b1-4b7f-87da-1dc63c704047 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology A revised estimate of the occurrence rate of terrestrial planets in the habitable zones around kepler m-dwarfs
Reference 13
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 56dee30f-83f5-447b-aaf6-3f307ed44c51 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Subsurface Exolife
Reference 14
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation e80bbf73-9a51-4b2d-a850-008929cca801 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Unresolved cited work
Reference 15
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation ad60575e-e32e-465a-a0de-729ebbb05e6e · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Unresolved cited work
Reference 16
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation ae759a0e-9ae8-42de-996e-e6cd3908e0c5 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Schulze-Makuch and L
Reference 17
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation e77fd9a8-df33-4170-a07a-7a08f0405079 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Bains, Many chemistries could be used to build living systems, Astrobiology 4, 137 (2004) doi:10.1089/153110704323175124
Reference 18
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation aca7f93d-5101-4311-b93c-5daed5113cb6 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology West, Multiple bonds to silicon: 20 years later, Polyhe- dron 21, 467 (2002) doi: 10.1016/S0277-5387(01)01017-8
Reference 19
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation 7a754f93-9db7-4991-b499-0b227530a759 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Lickiss, The synthesis and structures of organosilanols Adv
Reference 20
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation 56f87412-c79c-4e2f-b2d1-84414cc43977 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Okazaki, T
Reference 21
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation c175b8a8-21b3-4205-b602-a928aad102cf · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Unresolved cited work
Reference 22
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 50a6b582-7a5a-4c59-8d10-309352a5d604 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Unresolved cited work
Reference 23
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation fefa1f5d-2d6c-46ec-8b19-ca57f3942d4b · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Unresolved cited work
Reference 24
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation 22e0510b-8331-4b51-bfeb-34abac96bcc1 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Galactic Stellar and Substellar Initial Mass Function
Reference 25
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation dd26a4b7-e787-45c0-ad6a-5272cfda548d · outbound
Upper limit on the fraction of alien civilizations that develop communication technology A comprehensive comparison of the Sun to other stars: searching for self-selection effects
Reference 26
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation 1f70d0c9-5a83-495c-9b31-bf964c77b89d · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Unresolved cited work
Reference 27
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 1ccd5305-c20c-42e1-836b-9f5c14caebcf · outbound
Upper limit on the fraction of alien civilizations that develop communication technology A Dying Universe: The Long Term Fate and Evolution of Astrophysical Objects
Reference 28
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation d2cd189c-515b-4f1c-af8e-446e1366d995 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Relative Likelihood for Life as a Function of Cosmic Time
Reference 29
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation 1b86889e-93f0-45a3-8040-a8d3f4cd3319 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Fujii, D
Reference 30
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 5fa1f7ef-551b-4a11-b4fa-815083f9cb4f · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Physical constraints for the evolution of life on exoplanets
Reference 31
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation db85434f-e362-4c1e-ab11-296c98378e52 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Stellar parameters for TRAPPIST-1
Reference 32
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation b4e79528-acfa-4502-950d-7bee1cb38db6 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Improved Estimates of the Milky Way's Stellar Mass and Star Formation Rate from Hierarchical Bayesian Meta-Analysis
Reference 33
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 2f2e6079-9424-4bea-b1a0-7fde0ae9d5d7 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Toward a Unification of Star Formation Rate Determinations in the Milky Way and Other Galaxies
Reference 34
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 2a45b6bc-ac22-44af-8290-d8b4ebebe811 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology The Initial Mass Function of Stars: Evidence for Uniformity in Variable Systems
Reference 35
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation ff1e7bae-4ebb-4122-93a6-283dad9995f7 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Galactic-Field IMFs of Massive Stars
Reference 36
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 9b642b84-e477-40ae-acee-b76d870c7697 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Star Formation in the Local Milky Way
Reference 37
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation 6905f183-b771-458a-9817-34986a97840c · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Star Formation in the Milky Way and Nearby Galaxies
Reference 38
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation d4e610c3-e1c9-4e80-b2ee-852ac6b0226d · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Unresolved cited work
Reference 39
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation fd96599c-51a2-48da-ab56-02bae6fbe5e9 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Terrestrial Implications of Cosmological Gamma-Ray Burst Models
Reference 40
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation cd9a6f09-eae4-49d4-a741-d3b2d89c7980 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Life Extinctions By Cosmic Ray Bursts
Reference 41
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation c077c3bf-835f-4ea0-aaf9-1ff5d7f94579 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Terrestrial Ozone Depletion Due to a Milky Way Gamma-Ray Burst
Reference 42
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation c12c1316-af8c-406d-9bb4-e51809fb86e7 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Gamma-Ray Bursts and the Earth: Exploration of Atmospheric, Biological, Climatic and Biogeochemical Effects
Reference 43
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation d59422ba-1fe7-4f5c-99a8-2751d6970f86 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Did a gamma-ray burst initiate the late Ordovician mass extinction?
Reference 44
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation ad16f526-a64b-48b3-a4a2-a4502c8c4abd · outbound
Upper limit on the fraction of alien civilizations that develop communication technology On the role of GRBs on life extinction in the Universe
Reference 45
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation bacbb029-718b-4dda-bd68-34a607a638e0 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Unresolved cited work
Reference 46
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation a6f1c237-bea4-45ee-b19d-ad32206c6988 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Unresolved cited work
Reference 47
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation ddbc5bd5-b44a-4b9a-b41a-dda5af431865 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Galactic Neutrino Communication
Reference 48
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation b842f634-c0a5-413a-b3cf-13dbbe44cd49 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology A Unified Approach to the Classical Statistical Analysis of Small Signals
Reference 49
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 7034390f-0bae-477b-a7b2-9752d242d96d · outbound
Upper limit on the fraction of alien civilizations that develop communication technology The Breakthrough Listen Search for Intelligent Life: Target Selection of Nearby Stars and Galaxies
Reference 50
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation 2464e069-5c71-4368-8e55-2dd992400d59 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology The Breakthrough Listen Search for Intelligent Life: Searching Boyajian's Star for Laser Line Emission
Reference 51
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-14T06:32:32.682623+00:00.
Observation 27fd1ffb-e660-4bc8-808c-94c1bbf6f3a0 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology The Breakthrough Listen Search for Extraterrestrial Intelligence
Reference 52
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 79f228d6-4004-434b-b9e2-1a05bed05e33 · outbound
Upper limit on the fraction of alien civilizations that develop communication technology Searching the Moon for Extrasolar Material and the Building Blocks of Extraterrestrial Life
Reference 53
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
No inbound Pith citation observations are available.