1. Bacopoulos, A., Godini, G. and Singer, I., On best approximation in vector-valued norms, Colloquia Mathematica Societatis János Bolyai, 19, 89, 1978.
2. Bacopoulos, A., Godini, G. and Singer, I., Infima of sets in the plane and applications to vectorial optimization, Revue Roumaine de Mathématiques Pures et Appliquées, 23, 343, 1978.
3. Bacopoulos, A., Godini, G. and Singer, I., On infima of sets in the plane and best approximation, simultaneous and vectorial, in a linear space with two norms, in: Special Topics of Applied Mathematics, Frehse, J., Pallaschke, D. and Trottenberg, U., Eds., North-Holland, Amsterdam, 1980.
4. Bacopoulos, A. and Singer, I., On convex vectorial optimization in linear spaces, Journal of Optimization Theory and Applications, 21, 175, 1977.
5. Bacopoulos, A. and Singer, I., Errata corrige: On vectorial optimization in linear spaces, Journal of Optimization Theory and Applications, 23, 473, 1977.