WordPress The Loop

http://www.elegantthemes.com/blog/tips-tricks/the-wordpress-loop-explained-for-beginners
http://www.creativebloq.com/wordpress/master-wordpress-loop-7122985
http://code.tutsplus.com/articles/getting-the-most-of-post-formats-using-post-formats-in-the-loop–wp-34879
https://codex.wordpress.org/The_Loop_in_Action