The Elements of UML 2.0 Style is an ideal quick reference describing UML modeling guidelines.

The Elements of UML 2.0 Style is an ideal quick reference describing UML modeling guidelines.
The Elements of UML Style describes a collection of standards, conventions, and guidelines for creating effective UML diagrams.
The Object Primer 3e is a straightforward, easy-to-understand introduction to agile using object-oriented (OO) and relational database technologies.