Multiwavelength optical observations of chromospherically active binary systems - I. Simultaneous Hα, Na i D1, D2, and He i D3 observationsD. Montes, M. J. Fernández-Figueroa, E. De Castro and J. Sanz-ForcadaAstron. Astrophys. Suppl. Ser., 125 2 (1997) 263-287DOI: https://doi.org/10.1051/aas:1997374