The broadest way to search for information in an online catalog is by keyword. To search by keyword, consider the following tips:

• If your paper's theme is "The Land Reform Program of Emiliano Zapata," your keyword should be "Emiliano Zapata," not "Land Reform."
• "Land Reform" is not a good keyword because it will give you a list of books and articles about land reform in general. You will get books about land reform in many countries and at many periods of time.
• The keyword "Emiliano Zapata" will give you sources about him only. These books will probably include information about his land reform program because it was one of the important aspects of his career.
• Take the time to find a keyword that gives you sources that focus directly on your theme.