We present the results of a study of e(+)e(-)mu(+)mu(-) final states produced in e(+)e(-) collisions at a center-of-mass energy of 58 GeV using the AMY detector at TRISTAN. The data correspond to a total integrated luminosity of 292.8 pb(-1). The results show good agreement with order alpha(4) QED predictions. (C) 1998 Published by Elsevier Science B.V. All rights reserved.