1. A. Bacopoulos, G. Godini and I. Singer, “On best approximation in vector-valued norms”, Colloquia Mathematica Societatis Jânos Bolyai 19 (1978) 89–100.
2. A. Bacopoulos, G. Godini and I. Singer, “Infima of sets in the plane and applications to vectorial optimization”, Revue Roumaine de Mathématiques Pures et Appliquées 23 (1978) 343–360.
3. A. Bacopoulos, G. Godini and I. Singer, “On infima of sets in the plane and best approximation, simultaneous and vectorial, in a linear space with two norms”, in: J. Frehse, D. Pallaschke and U. Trottenberg (ed.), Special Topics of Applied Mathematics ( North-Holland, Amsterdam, 1980 ).
4. ] A. Bacopoulos and I. Singer, “On Convex Vectorial Optimization in Linear Spaces”, Journal of Optimization Theory and Applications 21 (1977) 175–188.
5. A. Bacopoulos and I. Singer, “Errata Corrige: On Vectorial Optimization in Linear Spaces”, Journal of Optimization Theory and Applications 23 (1977) 473–476.