Remember, reference materials are exactly that, for reference. They do not go very in-depth into a topic, so other non-reference resources should be used to support info from reference materials.
These books are available. Also, note that while the encyclopedias include basic info on a lot of gods, they don't go into much detail.
Critical Survey of Mythology and Folklore by 
The Facts on File Encyclopedia of World Mythology and Legend by 
Dictionary of Gods and Goddesses by 
