I liked this one:

REST API Design Rulebook, Designing Consistent RESTful Web Service Interfaces, by Mark Masse http://shop.oreilly.com/product/0636920021575.do

I'm not an expert. Here's a few resources I've collected:

http://www.restapitutorial.com/

http://www.restapitutorial.com/media/RESTful_Best_Practices-...

REST API Design Rulebook: http://shop.oreilly.com/product/0636920021575.do

RESTful Web Services: http://shop.oreilly.com/product/9780596529260.do

http://restcookbook.com/

https://en.wikipedia.org/wiki/Representational_state_transfe...