A framed f ( 3 , 1 ) -structure on tangent manifolds. Gîrţu, Manuela; Gîrţu, Valentin — 2008 Acta Mathematica Academiae Paedagogicae Nyí regyháziensis. New Series [electronic only]
Spherically symmetric generalized Lagrange metrics. Gîrţu, Valentin; Gîrţu, Monica — 1997 Balkan Journal of Geometry and its Applications (BJGA)