Four colour photometry of late-type binary systems - I. First light curves of ZZ Ursae MajorisR. Clement, M. García, V. Reglero, J. V. Clausen, A. Bravo, J. Suso, J. Fabregat, J. M. Torrejón, P. Reig and A. MarcoAstron. Astrophys. Suppl. Ser., 123 1 (1997) 1-4DOI: https://doi.org/10.1051/aas:1997341