Schaum's outline of theory and problems of combinatorics 2026-02-16T11:25:31+03:00 DEBUG: VuFind\ILS\Driver\Folio: Token taken from global cache: eyJhbGciOiJIUzI1NiJ9.eyJzdWIiO... - Balakrishnan, V. K., 1931- (McGraw-Hill, 1995)