| (525c),(525d) | Summaries of articles published in this issue. | 
| 525,526-541 | $L_p$-theory for a class of singular elliptic differential operators. Triebel, Hans | 
| 542-566 | On multiplication of Perron-integrable functions. Kurzweil, Jaroslav | 
| 567-573,574 | On Denjoy property and on approximate partial derivatives. Mukhopadhyay, S. N. | 
| 575-610 | Completions, translational hulls and ideal extensions of inverse semigroups. Schein, Boris M. | 
| 611-614 | Translation structures and group partitions. Bureš, Jarolím | 
| 615-616 | On the spectral function of a normal operator. Pták, Vlastimil; Vrbová, Pavla | 
| 617-628 | Ternary rings with zero associated to translation planes. Klucký, Dalibor; Marková, Libuše | 
| 629-634 | On the intersection of the sets of the right and left internal approximate derivatives. Zajíček, Luděk | 
| 635-669 | Periodic solutions to abstract differential equations. Straškraba, Ivan; Vejvoda, Otto | 
| 670-689 | Algorithmic algebras of computers. Čulík, Karel |