Medline - the comprehensive medical database from the US National Library of Medicine OCLC - Online Computer Library Center, Inc. There are over 6,700 libraries in 28 countries using the vast resources of the OCLC WorldCat database and the largest online ILL system British Library - the largest document supply service in the world. Types of service 1. Standard service SUPPLY 1 does not provide a guaranteed delivery time. However, reasonable efforts will be made to obtain the documents as soon as possible. Depending on the source of supply, delivery times will vary from 2 to 14 days or longer for difficult to locate documents. 2. Indicate the type of service, method of delivery and include a copyright declaration.