Moshe Leshno Vladimir Ya. Lin Allan Pinkus Shimon Schocken Multilayer feedforward networks with a nonpolynomial activation function can approximate any function. 861-867 1993 6 Neural Networks 6 http://dx.doi.org/10.1016/S0893-6080(05)80131-5 db/journals/nn/nn6.html#LeshnoLPS93