Masers as probes of proto-planetary discs Richards, A. M. S. ; Cohen, R. J. ; Crocker, M. ; Lekht, E. E. ; Samodourov, V. ; Berulis, I. I. ; Lobanov, A. ; Moscadelli, L. Abstract Publication: Planetary Systems in the Universe Pub Date: 2004 Bibcode: 2004IAUS..202..362R