Why Has the Generalized Electrical Machine Theory Not Been Universally Accepted?

Kron G. ., Application of Tensors to the Analysis of Rotating Electrical Machinery. G.E. Review

Fitzgerald A. E. , and Kingsley C. ., Electrical Machinery. McGraw-Hill

Stephens D. D. , and Levy J. F. ., A View from Industry on the Teaching of Electrical Machine Theory. ‘The Teaching of Electrical Machine Theory’ Conference at Queen Mary College, London, September 1961