A normalized LCCN is a character string eight to twelve characters in length. (For purposes of this description characters are ordered from left to right -- "first" means "leftmost".)
The rightmost eight characters are always digits.
If the length is 9, then the first character must be alphabetic.
If the length is 10, then the first two characters must be either both digits or both alphabetic.
If the length is 11, then the first character must be alphabetic and the next two characters must be either both digits or both alphabetic.
If the length is 12, then the first two characters must be alphabetic and the remaining characters digits.
Go to theLibrary of Congress Home Page
Library of Congress