Apostol / Douglas / Nagy / Voisulescu, Invariant Subspaces and Other Topics : 6th International Conference on Operator Theory, Timisoara and Herculane (Romania), June 1-11, 1981. Softcover reprint of the original 1st ed. 1982. (Operator Theory: Advances and Applications) 229 pp. (Springer Basel, SZ) ＜M25-18540＞

Foulds, L. R., Combinatorial Optimization for Undergraduates. Softcover reprint of the original 1st ed. 1984. (Undergraduate Texts in Mathematics) 228 pp. (Springer-Verlag New York Inc., US) ＜M25-18545＞