Citation Style

Citation style is part of the site’s trust layer. A citation should tell the reader why a source is being used: standard pedagogy, theorem-level precision, historical attribution, experimental evidence, software documentation, or current research context.

Source Roles

Use sources according to their role:

primary papers for priority, historical claims, and original experimental or theoretical results,
standard textbooks for settled formalism and pedagogy,
reviews and monographs for research areas and advanced synthesis,
rigorous mathematical references for hypotheses, domains, spectra, and theorem statements,
official documentation for software, data, standards, and APIs,
lecture notes for supplementary exposition, maintained open resources, or distinctive convention choices.

Do not cite a source only because it is famous. A reference should support a claim, guide further reading, document a convention, or identify a derivation route.

Books and Monographs

Format:

Author, *Title*, edition if relevant, publisher, year.

Use editions when formulas, chapter numbers, or problem references depend on them. If a book has many editions, cite the edition actually used.

Example:

J. J. Sakurai and J. Napolitano, *Modern Quantum Mechanics*, 3rd ed., Cambridge University Press, 2020.

Journal Papers

Format:

Author, "Paper title," *Journal* volume, page range or article number (year), DOI: linked DOI.

Use the DOI when available. Use arXiv links for preprints, open versions, or papers whose arXiv version is the stable public access route.

Example:

J. S. Bell, "On the Einstein Podolsky Rosen Paradox," *Physics* 1, 195-200 (1964), DOI: [10.1103/PhysicsPhysiqueFizika.1.195](https://doi.org/10.1103/PhysicsPhysiqueFizika.1.195).

arXiv and Preprints

For arXiv-only sources, include the arXiv identifier and version when the version matters. If a paper later appears in a journal, cite the journal version and include the arXiv link only when open access is useful.

Use preprints carefully for active research. Mark frontier claims as active, conjectural, controversial, or speculative when the literature has not settled.

Lecture Notes and Web Resources

Format:

Author or institution, *Title*, institution or course when relevant, URL.

Use an access date when the content is a living webpage and the cited claim depends on its current form. For stable PDFs with versions or dates, cite the version instead.

Lecture notes should not usually be the sole source for theorem-level claims, historical priority, or experimental status.

Software, Data, and Standards

For software, cite:

the package paper if one exists,
official documentation,
version number used for reproducible results,
repository or DOI for archived releases when available.

For physical constants, units, and standards, cite official standards bodies or authoritative databases, not secondary summaries. The Constants, Units, and Conventions pages should carry these citations.

Historical Sources

Historical claims should distinguish:

the original primary source,
a modern reconstruction,
a textbook simplification,
a later experimental confirmation or correction.

When using old sources, do not silently modernize their terminology in quotation-like prose. Prefer paraphrase with context, and use modern notation only after saying that a translation has been made.

Internal Links versus Citations

Use internal links for canonical explanations inside the site. Use external citations for source authority. For example, a formula page should link to the canonical derivation page and cite the textbook or paper that supports the formula’s standard status.

Do not duplicate a derivation only because another source derives it differently. Link to the canonical derivation and add a convention note if needed.

Citation Anti-Patterns

Citation padding: listing sources that were not used.
Review-only history: citing a modern review for original discovery when primary papers are available.
Textbook-only frontier claims: citing an old textbook for a topic that has changed.
Lecture-note authority drift: using notes for a theorem or experimental claim when a stronger source exists.
Missing convention role: citing a formula without saying which units, normalization, or sign convention it uses.

Cross-Links

References

M. Jammer, The Conceptual Development of Quantum Mechanics, 2nd ed., American Institute of Physics, 1989.
J. Mehra and H. Rechenberg, The Historical Development of Quantum Theory, Springer, 1982-2001.
J. J. Sakurai and J. Napolitano, Modern Quantum Mechanics, 3rd ed., Cambridge University Press, 2020.
M. Reed and B. Simon, Methods of Modern Mathematical Physics I: Functional Analysis, revised and enlarged ed., Academic Press, 1980.