Using the ARGUS detector at the e+e storage ring DORIS II, we have measured the Michel parameters , , and for ! l decays in -pair events produced at center of mass energies in the region of the resonances. Using ! as spin analyzing tags, we nd e = 0:68 0:04 0:08, e = 1:12 0:20 0:09, e = 0:57 0:14 0:07, = 0:69 0:06 0:08, = 1:25 0:27 0:14 and = 0:72 0:18 0:10. In addition, we report the combine...