Most of the sources listed below are in the Aisia Reading Room in Kroch Library. (The "REF" in the call number indicates that it is a reference book.) Otherwise, books are in the Asia book stacks. Items with blue titles are available as e-books -- click on the title.
Maps of Southeast Asia are available in print format in the Maps Room (lower level of Olin Library) and online.
The Southeast Asia countries section of the Asia Collections web site has links to individual countries. For each country, there is a list of sources which may include introductory items, databases, government documents and sources (British, U.S.), book chapters from edited books (organized by subject) and other sources.