i would say starke is an authority. He has written short and accurate but easy....You can take his book....
But i must say this subject does not require your background in law, so please don't study one book for it....Make your own notes out of at least 2 books so that you get too know the point of views of different jurists and law makers.....That's what these days examiners are requiring....Rest is ur decision....

Regards

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“The greatest discovery of all time is that a person can change his future by merely changing his attitude.”