64 Baker Street is an independent historical reference project dedicated to the Special Operations Executive (SOE) and the people, operations, resistance networks, organizations, locations, technologies, and archival records associated with its activities during the Second World War.
Sources are fundamental to this project.
Our objective is not simply to tell compelling historical stories, but to make clear where important information comes from, how strongly the available evidence supports it, and where readers can continue the research themselves.
This policy explains the types of sources we use, how we evaluate them, how archival references are presented, and how citations should be handled throughout 64 Baker Street.
Why We Cite Sources
Historical citations serve several purposes.
They allow readers to distinguish documented evidence from interpretation. They make it possible to verify important claims. They acknowledge the work of archives, historians, researchers, photographers, and other creators. They also provide a path for future research.
The National Archives emphasizes that precise and consistent references help demonstrate that historical research rests on documentary evidence and enable other researchers to identify records, verify information, and continue the research.
64 Baker Street follows the same principle.
A citation should not merely make an article look authoritative.
It should help a reader find the evidence.
Our Source Hierarchy
Not every source has the same evidentiary value.
The appropriate source also depends on the claim being made. A personnel file may be the best source for an agent’s service history, while an operational report may be more useful for reconstructing a mission. A later scholarly work may be necessary to understand wider political consequences.
As a general guide, our research preference moves through the following hierarchy:
- Primary archival records and contemporary documents — personnel files, operational reports, correspondence, signals, memoranda, wartime photographs, mission reports, diaries, letters, official records, and similar contemporary evidence.
- Official archives and institutional collections — The National Archives, Imperial War Museums, National Army Museum, national archives outside the United Kingdom, university special collections, military archives, and comparable institutions.
- Official histories and scholarly publications — official historical studies, peer-reviewed journal articles, academic monographs, and research published by established historians.
- Specialist secondary works — carefully researched biographies, histories, memoirs, reference works, and specialist publications that identify their evidence.
- Reputable digital sources — established historical projects and institutional websites used for supplementary evidence or research discovery.
- General reference sources — encyclopedias, collaborative databases, and similar sources used principally for orientation and discovery rather than as the sole support for important disputed claims.
This hierarchy is a guide rather than an automatic ranking system.
A contemporary document can contain an error. A later historian may discover records unavailable to an earlier official history. An eyewitness may remember something incorrectly. A modern institutional catalogue may correct a description published decades earlier.
Every source must therefore be evaluated in context.
Primary Sources
Primary sources are especially valuable to 64 Baker Street.
Depending on the subject, these may include SOE personnel files, operational reports, training assessments, correspondence, message traffic, contemporary intelligence reports, government memoranda, photographs, aircraft records, resistance reports, diaries, letters, and documents produced during or shortly after the events concerned.
Primary does not mean infallible.
Wartime records may contain incomplete intelligence, operational cover names, incorrect dates, clerical errors, assumptions, deliberate deception, or information recorded before the full outcome of an operation became known.
We therefore avoid treating a document as unquestionably correct merely because it was created at the time.
The National Archives
The National Archives is one of the principal sources for research concerning the Special Operations Executive.
Its intelligence research guidance identifies HS as the departmental reference code for Special Operations Executive records. SOE personnel files are principally found within HS 9, while related material may also appear in records of the Foreign Office, Air Ministry, War Office, Cabinet, and other government departments.
When citing a record held by The National Archives, 64 Baker Street follows its guidance wherever practical.
The archive recommends recording:
The institution + full catalogue reference + relevant internal identifier where available.
Catalogue references should be reproduced exactly as they appear in Discovery, including their spacing and punctuation.
Example
A basic archival citation may appear as:
The National Archives (TNA), HS 9/[file reference].
Where an individual page or folio has been identified:
The National Archives (TNA), HS 9/[file reference], f 12.
or:
TNA, HS 9/[file reference], pp 18–21.
The actual reference used must be verified against the catalogue or record concerned.
Placeholder references such as those above are examples of format only and must never be published as though they identify a real file.
Use the Lowest Useful Catalogue Level
Where possible, we cite the most specific available catalogue reference relevant to the statement.
The National Archives recommends normally citing the lowest useful level in its catalogue hierarchy and retaining internal page, folio, item, docket, or similar identifiers where these help locate the relevant evidence.
This is preferable to citing an entire broad series when the evidence actually comes from one identifiable file.
For example, citing simply:
HS 9
is less useful than citing the specific personnel file when that file is known.
Catalogue Entry vs. Original Document
64 Baker Street makes an important distinction between:
a catalogue entry
and
the archival document described by that entry.
Finding a record in an online catalogue may verify the record’s title, reference, date range, archival location, and description.
It does not necessarily mean that we have examined the contents of the underlying file.
When our evidence comes only from the catalogue description, we should not write as though the complete archival record has been personally inspected.
Where relevant, articles may use wording such as:
The National Archives catalogue identifies the file as…
rather than:
The file states…
unless the underlying document has actually been consulted.
Citing Discovery Catalogue Entries
Sometimes the catalogue entry itself contains information relevant to an article.
The National Archives recommends that citations to Discovery entries identify the catalogue, reference, title or description, relevant catalogue field, URL, and date accessed where appropriate.
64 Baker Street may use a simplified reader-facing form while preserving sufficient information in editorial records.
For example:
The National Archives, Discovery, HS 9/[reference], [record title], accessed [date].
The article may link directly to the relevant catalogue entry whenever this improves the reader’s ability to verify the reference.
SOE Personnel Files
SOE personnel files deserve particular attention because they form the foundation of many biographies.
The National Archives states that personnel records can be searched within HS 9 by name and year of birth. It also notes that restrictions can apply to records relating to individuals who may still be alive.
A personnel file may help establish facts such as recruitment, training, evaluations, aliases, assignments, or wartime service.
However, not every biographical statement should automatically be attributed to the personnel file as a whole.
Whenever possible, we identify the particular document, report, page, or section supporting a significant claim.
Records Outside the HS Series
SOE history cannot always be reconstructed from HS records alone.
A mission may also be documented in:
AIR records relating to aviation, WO records relating to military activity, FO records concerning diplomatic matters, CAB records dealing with government decisions, or records held by foreign archives and resistance organizations.
The National Archives warns researchers that subjects may cross multiple government departments and therefore appear in more than one record series.
For that reason, 64 Baker Street does not assume that a search of one SOE collection constitutes an exhaustive investigation.
Imperial War Museums
Imperial War Museums can be particularly important for photographs, objects, oral histories, documents, weapons, equipment, uniforms, and other material culture.
When citing an IWM collection object, we aim to record the identifying information supplied in the collection catalogue, including the object title or description and its catalogue number.
IWM itself notes that its online collection records continue to evolve: new information may be added, interpretations may change, and errors may be corrected.
This reinforces an important principle of our own research: catalogue descriptions are valuable evidence, but they too can be revised.
Image Licensing Is Separate From Citation
Citing an image does not automatically give permission to reproduce it.
Copyright, licensing, and attribution requirements must be considered separately.
For example, IWM makes some collection material available under particular reuse conditions, while other material may require additional permission or licensing. Its non-commercial licence requires appropriate acknowledgement and applies only to material specifically made available under that licence.
Likewise, The National Archives notes that reproduction of archive material may require consideration of copyright ownership, permissions, acknowledgement, and document references.
64 Baker Street therefore treats:
historical sourcing,
copyright,
and
permission to reproduce
as related but separate questions.
Photographs
Photographic citations should be as specific as possible.
Where known, we aim to identify the photograph’s subject, photographer or creating organization, approximate or exact date, holding institution, catalogue or object number, and relevant rights information.
An ideal credit might therefore resemble:
Imperial War Museums, [collection/object number], [photographer if known].
The exact form depends on the institution’s required attribution.
We do not assume that a photograph is public domain merely because it is old or widely reproduced online.
Books
Books remain important secondary sources for SOE research.
A citation should normally make it possible to identify:
author, title, publisher, edition where relevant, year, and page number where available.
For example:
Author, Book Title (Publisher, Year), pp. 120–124.
For statements relying heavily on one particular passage, page-level citation is strongly preferred.
Citing an entire 500-page biography without a page number may technically identify the source but provides little assistance to the researcher trying to verify a specific claim.
Journal Articles
Academic journal citations should normally identify:
author, article title, journal title, volume or issue where relevant, publication year, and page range or persistent identifier.
A DOI may be included when available.
Peer review does not make an article immune from error, but scholarly articles can be particularly valuable for disputed questions because they often explain evidence and historiographical disagreements in detail.
Official Histories
Official histories occupy an important place in SOE scholarship.
They may draw on records and institutional knowledge unavailable to contemporary public accounts.
However, “official” does not mean “final.”
Later archival releases and scholarship may revise conclusions reached in an earlier official history.
Where an important modern interpretation differs from an official history, both may be cited and the difference explained.
Memoirs and Autobiographies
Memoirs provide valuable firsthand testimony but should be clearly identified as recollection.
Where a memoir is the basis of a claim, wording may indicate that attribution:
According to X’s later memoir…
or:
X later recalled that…
This prevents a recollection written decades after an event from being presented as if it were a contemporary operational report.
Page numbers should be supplied whenever practical.
Oral Histories and Interviews
Oral histories should identify the interviewee, interviewer or collecting institution where known, date, collection, reference number, and relevant recording or transcript location.
We also consider when the interview was recorded.
An interview conducted in 1985 about an event in 1944 is valuable evidence, but it is not contemporaneous evidence.
Newspapers
Historic newspapers may be used for public announcements, obituaries, court proceedings, awards, local reporting, and contemporary reactions.
A useful newspaper citation should normally identify:
publication, article title where available, date, and page where known.
Wartime reporting must be interpreted in the context of censorship, propaganda, operational secrecy, and incomplete public information.
Websites
Web sources are used selectively.
Preference is given to:
- archives;
- museums;
- universities;
- government institutions;
- established historical organizations;
- specialist projects that identify their own evidence.
For significant historical claims, a generic website should not normally replace a stronger archival or published source when one is readily available.
Where an online source is likely to change, we may preserve an access date.
Web Archives
Historical web pages can be valuable when researching older digital resources, including earlier versions of 64-baker-street.org.
Where an archived webpage is used, we try to identify both the original site and the archived capture.
A citation may include:
page title, original website, archived version or repository, capture date, and archived address.
Archived web pages must still be evaluated critically.
The fact that a statement appeared on an old website does not establish that it was historically accurate.
Wikipedia and Collaborative References
Wikipedia and comparable resources can be useful research-discovery tools.
They may help identify:
alternative spellings, published books, archive references, relevant individuals, operations, and search terminology.
They should not ordinarily be the sole source for a disputed or significant claim when the cited underlying evidence can be consulted.
Where Wikipedia points to a book, archive, journal article, or institutional record, we prefer to examine and cite that underlying source.
Search Results and Snippets
Search-engine result snippets are not treated as reliable historical sources.
A snippet may be truncated, automatically generated, outdated, or presented without necessary context.
Researchers should open the underlying page and verify the statement there.
The same principle applies to automatically generated search summaries.
Artificial Intelligence
Artificial intelligence is not a citable historical authority for 64 Baker Street.
AI systems may assist with research organization, drafting, search-term generation, or locating subjects requiring investigation.
They can also invent books, quotes, dates, people, operations, and archive references.
The National Archives explicitly warns that AI chatbots can provide false information or hallucinated archive references and advises researchers to verify document references in its catalogue.
Therefore:
We do not cite an AI system as evidence for a historical fact.
Any factual information first suggested by an AI tool should be verified against an appropriate source before publication.
Any archival reference suggested by AI must be independently checked against the relevant catalogue.
Multiple Sources Repeating the Same Claim
Five websites repeating one statement do not necessarily constitute five independent sources.
They may all derive from the same book, memoir, Wikipedia entry, press article, or earlier website.
For important claims, we try to identify whether apparently independent sources share a common origin.
Where possible, we cite the earliest or strongest underlying source rather than the chain of repetition.
Conflicting Sources
When reliable sources disagree, citations should help readers understand the disagreement rather than conceal it.
For example:
One wartime report gives the operation date as 14 June, while the later official history gives 15 June.
Both sources may then be cited.
If we favor one interpretation, the article should explain why where the distinction is important.
Where the evidence remains genuinely unresolved, we may state that no definitive conclusion can presently be reached.
Sources We Treat With Particular Caution
Anonymous websites, unsourced social-media posts, copied biography pages, generated content, commercial pages with no editorial provenance, forum discussions, family stories without supporting documentation, and unattributed quotations may provide useful research leads.
They do not automatically provide sufficient evidence for publication.
A forum post might lead us to the name of an agent.
That name can then be investigated in archival catalogues.
The archival evidence—not the forum post—should become the basis of the article if it can be verified.
Citations Should Support the Claim They Follow
A source should actually support the statement to which it is attached.
We avoid “citation laundering,” where a reputable institution is cited at the end of a paragraph even though that institution does not establish the paragraph’s principal claim.
When a paragraph contains several distinct factual statements derived from different sources, separate citations may be appropriate.
Page-Level Citations
Whenever practical, books and long documents should be cited to the specific page or relevant range.
This is especially important for:
direct quotations, disputed claims, exact statistics, unusual biographical details, and interpretations attributed to another historian.
General background claims may occasionally be supported by a work as a whole, but precise references are preferable.
Direct Quotations
Direct quotations must reproduce the source accurately.
Minor omissions should be clearly indicated where appropriate.
Translations should not be presented as though they are the original wording.
Where we provide our own translation, this may be identified as such.
Quotations should be used selectively. Paraphrasing with a precise citation is often preferable to reproducing lengthy copyrighted passages.
Citation Does Not Mean Endorsement
Citing a source means that the source is relevant to the statement or discussion.
It does not mean that 64 Baker Street agrees with everything contained in that source.
An article examining a disputed historical claim may cite a source specifically to explain why its account differs from other evidence.
Source Notes and Further Reading
Depending on the subject, an article may contain separate areas for:
Sources, Archival References, or Further Reading.
These serve different purposes.
Sources identify material directly used to support the article.
Archival References highlight primary records and catalogue entries relevant to the subject.
Further Reading may include useful scholarship that provides broader context even if it was not directly cited for every statement in the article.
We avoid filling bibliographies with books that were not actually consulted merely to create an appearance of extensive research.
Updating Citations
Links break. Archive catalogues change. Better editions become available. Collections are digitized. New records are opened.
Citations may therefore be updated even when the underlying historical conclusion remains unchanged.
Where a stronger primary source becomes available, we may replace or supplement a weaker secondary citation.
IWM itself notes that collection records are continually developed and sometimes corrected as new information becomes available.
Our citation system must be able to evolve in the same way.
Correcting Source Errors
If we discover that:
a source was misquoted, an archive reference was incorrect, a page number was wrong, a link pointed to the wrong record, or a cited source did not support the associated claim,
we aim to correct the citation.
When the sourcing error materially changes the historical conclusion of an article, the content itself should also be reviewed under our Corrections Policy.
Reader Contributions
Readers are welcome to suggest additional sources or point out possible citation problems.
The most helpful submissions identify:
the relevant 64 Baker Street page, the specific statement concerned, and the archival reference, publication, document, or other evidence that may clarify it.
We evaluate submitted sources according to the same standards applied to our own research.
Submission of a source does not guarantee that a claim will be changed, but credible evidence will be considered.
Independence and Attribution
64 Baker Street is an independent project.
Referencing The National Archives, Imperial War Museums, National Army Museum, universities, government archives, or other institutions does not imply that those organizations sponsor, approve, or endorse this website.
Their names are used because they hold, catalogue, publish, or preserve sources relevant to our research.
Our Citation Standard
Our goal is not to attach the largest possible number of references to an article.
It is to attach the right evidence to the right claims.
A strong citation should allow a reader to answer three questions:
What is the source?
What does it support?
Can I find it myself?
Wherever possible, 64 Baker Street aims to make the answer to all three clear.
Historical research is strongest when readers do not have to take an author’s word on trust.
They can follow the evidence.