Entry Topical Term

Number of records used in: 1

001 - CONTROL NUMBER

• control field: 28629

003 - CONTROL NUMBER IDENTIFIER

• control field: OSt

005 - DATE AND TIME OF LATEST TRANSACTION

• control field: 20220712205916.0

008 - FIXED-LENGTH DATA ELEMENTS

• fixed length control field: 220712|| aca||aabn | a|a d

040 ## - CATALOGING SOURCE

• Original cataloging agency: OSt
• Transcribing agency: OSt

150 ## - HEADING--TOPICAL TERM

• Topical term or geographic name entry element: Cryptography
• Geographic subdivision: Great Britain
• General subdivision: History
• Chronological subdivision: 20th century.

670 ## - SOURCE DATA FOUND

• Source citation: Work cat.: (OSt): Good, Irving John, author. 28628, Breaking teleprinter ciphers at Bletchley Park :