In considering " looseleaf" it is first of all necessary to distinguish between publications that are merely issued in looseleaf format (1) and those that are issued in this format for the specific purposes of updating. This online help deals only with the latter type, which is called "looseleaf for updating." For further discussion of this distinction, select from below:

Preliminary Notes

Library of Congress Treatment of "Looseleaf for Updating"

See also:

Cataloging Rules for the Description of Looseleaf Publications: Contents