[Haskell-cafe] Control.Alternative --- some and many?

Hey everyone, Could someone explain to me (or point me to a reference explaining) the purpose of the "some" and "many" methods of the Alternative class? Also, there is a link posted in the documentation for Control.Applicative to a paper which describes the motivation behind the Applicative class; is there similarly a paper explaining the motivation behind the Alternative class? (The problem with Googling for "Alternative" is that this word is used a whole lot of the time, and very rarely does it refer to the Alernative class. :-) ) Cheers, Greg