Kew Bibliographic Databases (Kew Record, Economic Botany..)
Agricola (National Agricultural Library’s)
ScienceDirect.com (25% of the world’s science, full text and bibliographic inf.)
Botany Libraries (Harvard University Herbaria)
ISI Web of Knowledge (Web of Science)
Scopus (database of research literature and quality web sources)
W3VAST Bibliography (TROPICOS, at the Missouri Botanical Garden)
Botanicus Digital Library (historic bot. literature, Missouri Botanical Garden Lib.)
Encyclopedias:
Encyclopedia.com (Columbia Encyclopedia)