Natural tensor fields of type ( 0 , 2 ) on the tangent and cotangent bundles of a semi-Riemannian manifold José Araujo; Guillermo Keilhauer — 2000 Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica
Natural tensor fields of type ( 0 , 2 ) on the tangent and cotangent bundles of a Fedosov manifold. Araujo, José; Keilhauer, Guillermo — 2006 Balkan Journal of Geometry and its Applications (BJGA)
Discrete and dense subgroup problems. (Problemas con subgrupos discretos y subgroupos densos.) Araujo, José O.; Fernández, Laura B. — 2006 Boletín de la Asociación Matemática Venezolana