Joe Celko's complete guide to NoSQL what every SQL professional needs to know about nonrelational databases by Celko, Joe

Available for University of the Philippines System via ScienceDirect. Click here to access
Also available remotely for University of the Philippines System via ScienceDirect. Click here to access thru EZproxy

Joe Celko's Trees and hierarchies in SQL for smarties by Celko, Joe

Joe Celko's SQL for smarties advanced SQL programming by Celko, Joe