| 509-516 | Commutative primary semigroups. Satyanarayana, M. |
| 517-521 | Sequences of disjoint open sets. Mrówka, S.; Tan, H. P. |
| 522-524 | A characterization of semilattices of left or right groups. Pondělíček, Bedřich |
| 525-534 | Notes on purities. Bican, Ladislav |
| 535-553 | Free products in varieties of lattice-ordered groups. Martinez, Jorge |
| 554-580 | The third boundary value problem in potential theory. Netuka, Ivan |
| 581-589 | Automorphismen von $X$-Summen von Graphen. Dörfler, Willibald |
| 590-599 | Second order differential equations with complex-valued coefficients. Ráb, Miloš |
| 600-611 | Über Eulersche und paare Hamiltonsche Graphen. Dorninger, Dietmar |
| 612-640 | Universal approximation by hill functions. Segeth, Karel |
| 641-652 | Deformation and equivalence $G$-structures. Part I. $\{e\}$-structures. Bureš, Jarolím |
| 653-662 | On canonical forms on non-holonomic and semi-holonomic prolongations of principal fibre bundles. Dekrét, Anton |
| 663-682 | Integrals of the Cauchy type. Král, Josef; Lukeš, Jaroslav |
| 683-687 | News and Notices. |
| (692),(693)-(694) | Summaries of articles published in this issue. |