Column L indicates a one-character code identifying a designated library or program. Examples include: D - Library of Congress (LC), P - Program for Cooperative Cataloging (PCC), M - National Library of Medicine (NLM), G - U. S. Government Printing Office, A - National Agricultural Library, U - British Library, C - National Library of Canada, T - National Central Library of Taiwan.
For more information, refer to the Searching & Sending Requests: Searching OCLC documentation under the Search Results section.