%0 Journal Article %A Smith, Roy %A Varley, Robert %T Deformations of theta divisors and the rank $4$ quadrics problem %J Compositio Mathematica %D 1990 %P 367-398 %V 76 %N 3 %I Kluwer Academic Publishers %U http://archive.numdam.org/item/CM_1990__76_3_367_0/ %G en %F CM_1990__76_3_367_0