Bibliographic database of citations to the agricultural literature created by the National Agricultural Library and its cooperators.

The National Library of Medicine (NLM), on the campus of NIH in Bethesda, Maryland, is the world's largest medical library. It collects materials in all major areas of the health sciences and to a lesser degree in such areas as chemistry, physics, botany and zoology. The collections stand at 5 million items--books, journals, technical reports, manuscripts, microfilms, photographs and images. Hous

The Library of Congress. The Library of Congress is the nation's oldest federal cultural institution, and it serves as the research arm of Congress. It is also the largest library in the world, with more than 120 million items. The collections include books, sound recordings, motion pictures, photographs, maps, and manuscripts.