References
1. http://bank.engzenon.com/download/53a98ee3-5b14-4e63-bb84-6e4ec0e8c6f8/Electric_Machinery_Fundamentals_-_5th_Ed_Chapman.pdf
2. http://cdn.tzty.net/b/ece240/3.pdf
1. http://bank.engzenon.com/download/53a98ee3-5b14-4e63-bb84-6e4ec0e8c6f8/Electric_Machinery_Fundamentals_-_5th_Ed_Chapman.pdf
2. http://cdn.tzty.net/b/ece240/3.pdf