Progress and New Directions for the Berkeley Supernova Search Perlmutter, S. ; Marvin, H. J. ; Muller, R. A. ; Pennypacker, C. R. ; Sasseen, T. P. ; Smith, C. K. ; Wang, L. P. Abstract Publication: Supernovae Pub Date: 1991 Bibcode: 1991supe.conf..727P