Guangshan, Xu, Simultaneous Approximation to Values of Exponential Function at Algebraic Points, Acta Mathematica Sinica, New Series Chinese Journal of Mathematics, 9(4), 1993, pp. 421-431
This paper applies the methods of Chudnovsky, Osgood and Baker to give a simultaneous approximation theorem to the values of exponential function at algebraic points, which slightly sharpens and generalises the results of Chudnovsky.