to order several kinds of material for libraries' collections, including maps, Braille, large print documents, foreign language items, and audio. Core Collection The Core Collection was established in 1977. Every depository library is required to have certain publications available for use. These include, among others: Budget of the United States Government Catalog of U.S. Government Publications Code of Federal Regulations Congressional Directory Congressional Record (daily) Federal Register (daily) Statistical Abstract of the United States United States Code Selecting items Libraries select the documents they wish to receive from the List of Classes of United States Government Publications Available for Selection by Depository Libraries and the Union List of Item Selections. This is a document listing all of the classes of items available for selection through the program and their associated item numbers. Each item with an item number is available through the FDLP program. Because of the large number of documents published by the government each year, the documents are arranged into categories of related classes from which to choose. By selecting a class, the library receives all of the documents within that class. Selections made during the year take effect on October 1. The Union List of Item Selections updates the titles in the List of Classes on a semiannual basis. Deselecting items Unlike adding items, selections may be removed at any time; the library stops receiving the documents within 72 hours. Retention of documents Selective depository libraries must keep government documents in their collections for five years minimum, after which time the items may be removed from the collection with the approval of a regional library. Items marked for disposal must be offered first to the regional, then to other depositories (). All depository libraries, including regional libraries, may dispose of items that have been superseded or issued later in bound form (). If an item has been deselected, the library must still retain the publications it possesses from that item number for five years before they may be discarded. Libraries may not financially benefit from the disposal of depository publications. Electronic documents After 1996, government publications increasingly shifted to online formats; in addition, most Federal publications now originate online. Regional libraries still continue to collect information in a wide variety of formats, but many government documents are now published exclusively online. Electronic documents positively impact issues such as storage, length of retention, and access, which can be