For Leadership research, ABI/Inform (Business) and ERIC (Education) are the top places to start. Use them to find scholarly articles, books, book chapters, conference proceedings, theses, dissertations, and more.
(Formerly ABI/Inform) Covers thousands of business publications, most of them in full-text. Subject coverage includes business conditions, management techniques, business trends, management practice and theory, corporate strategy and tactics, and competitive landscape.
The world's largest resource for peer-reviewed literature in behavioral science and mental health. Produced by the American Psychological Association. Indexes thousands of journals dating back to the 17th and 18th centuries, plus books, book chapters, and dissertations.