Basic Collections in Objective-C May 30th, 2012 https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/Collections/Articles/Arrays.html https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/Collections/Articles/Dictionaries.html https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/Collections/Articles/Sets.html https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/Collections/Articles/index.html