A Guide to Finding Business Information at the Library of Congress Guide to Business History Resources
"Researchers seeking historical information about an old company or an extinct firm have a fair bit of detective work to do. Some aids for such a search have been gathered together in the Business Reading Room reference collection and selected titles, primarily focusing on United States companies, are listed below. When available, links are included to online tables of contents, indexes, and lists of sources cited for those resources for which they are available. Links are also included to selected Internet resources relating to business history.

One should begin by searching for any works by or about the company in question in the Library of Congress online catalog, in the Main Card Catalog, and in appropriate bibliographies. Researchers should also consult standard indexes such as The New York Times Index, The Wall Street Journal Index, Business Periodicals Index, and the Social Science Index. In addition, researchers may consult several sets of company annual reports available on microfiche in Business Reference Services, including one covering the late 19th- and early 20th-centuries..."