This will take you to the LibGuide For the History of Photography with more information on the subject of Photography.
The Abrams Encyclopedia of Photography by 
The Photography Encyclopedia by 
The Concise Focal Encyclopedia of Photography by 
Critical Terms for Art History by 
The Focal Encyclopedia of Photography 3rd Ed. by 
Encyclopedia of Photography by 
Illustrated Dictionary of Photography by The database Oxford Reference Online includes several online encyclopedias that provide some great background information on your topic. If you begin by gaining some knowledge with these sources, you can get a better idea of the context and history of your topic, as well as some ideas for keywords to use in searching for more specific information later!
The Oxford Companion to the Photograph by 
You can also click on "Art & Architecture" (after clicking "Subject" on the top left of the blue bar) to find many more reference books on art topics, with entries related to photography (look for the option to "Search within work" to find photo-related information in more general art encyclopedias).
A Dictionary of Modern and Contemporary Art by 
Complete photographer, a complete guide to amateur and professional photography by 
Creative Black and White Photography by 
Each Wild Idea by 
The Focal Encyclopedia of Photography by 
History of Photography by 
The History of Photography by 
Photography: History and Theory by 
A Short Guide to Writing about Art by 
