ROS Wiki:

http://wiki.ros.org/

　　Robots Using ROS

Textbooks:

A Gentle Introduction to ROS

Learning ROS for Robotics Programming

　　1st Edition [pdf] [code] [ros wiki]

　　2nd Edition [code] [wiki] [online reading]

Blog / Tutorial　　

　　ROS 101: INTRO TO THE ROBOT OPERATING SYSTEM

　　TIAGo Tutorials

Learning Roadmap of Robotic Operating System (ROS)