See: Pramathanath Sastry, Correction to: "Regular differential and equidimensional scheme-maps",   J. Algebraic Geom. 14 (2005),   593--599.

Summary: This corrects a sign error in the paper "Regular differential and equidimensional scheme-maps",
J. Algebraic Geom. 1 (1992), 101--130 by J. Lipman and P. Sastry