High-velocity interstellar clouds towards the M 15 globular cluster - I. Low resolution optical dataN. Lehner, W. R.J. Rolleston, R. S.I. Ryans, F. P. Keenan, B. Bates, D. L. Pollacco and K. R. SembachAstron. Astrophys. Suppl. Ser., 134 2 (1999) 257-262DOI: https://doi.org/10.1051/aas:1999441