Geography for surfaces of general type in positive characteristic. N.I. Shepherd-Barron — 1991 Inventiones mathematicae
Unstable vector bundles and linear systems on surfaces in characteristic p. N.I. Shepherd-Barron — 1991 Inventiones mathematicae
Threefolds and deformations of surface singularities. N.I. Shepherd-Barron; J. Kollár — 1988 Inventiones mathematicae