Reference works such as handbooks, dictionaries, encyclopedias, directories, bibliographies, etc. provide useful background information which helps start your research.
Blackwell Reference Online - Collection of reference books across the social sciences and humanities, with a particular strength in handbooks, of which there are several hundred, including Blackwell Handbook of Childhood Cognitive Development, Blackwell Handbook of Language Development and The Handbook of Education and Human Development.
Sage Knowledge - An online collection of subject encyclopedias and handbooks covering a wide-variety of subjects in the social sciences. Browse by the subject area "Education" to view all the titles available.