Complex timelike isothermic surfaces and their geometric transformations. Dussan, Martha; Magid, Martin — 2006 Balkan Journal of Geometry and its Applications (BJGA)
Compact manifolds of nonnegative isotropic curvature and pure curvature tensor. Dussan, Martha; Noronha, Maria Helena — 2005 Balkan Journal of Geometry and its Applications (BJGA)