We present photoluminescence excitation spectra in undoped GaAsGa1-xAlxAs quantum wells in the presence of magnetic and electric fields perpendicular to the layers. The use of circularly polarized light allows us to separate the Zeeman components of the excitons and resolve closely lying lines in the spectra. The oscillator strength of the excited states of the heavy-hole exciton is increased by electric-field-induced coupling with the ground state of the light-hole exciton. By comparison with effective-mass-type calculations which take into account valence-band mixing and electric and magnetic-field effects, we are able to assign the peaks up to the 3d excited state. © 1988 The American Physical Society.