Help:How to create a link to a US Library of Congress (Loc) record

Most books published in the US have an assigned LCCN -- the Library of Congress Control Number (formerly Catalog Number). This is generally worth recording in the notes of the relevant publication.

For books published before 2001, the number is generally shown as a two-digit year, a hyphen, and a serial number of up to 6 digits. (There was a brief period in 1970-72 when the two digits did not show the year.)

For books after 2001-01-01, the year is given as 4 digits, and the hyphen is usually omitted.

A permanent link to the online LoC record for a given LCCN is formed as follows: " " or " ". The number in the URL should start with the 2 or 4-digit year, omit the hyphen, and pad the remaining number to 6 digits with leading zeros, if needed. Thus 45-7832 gives the URL, 76-89432 gives  , and 2007683290 gives   for a URL.

See the LoC's LCCN permalink FAQ for more detail.