Schaum's outline of theory and problems of partial differential equations 2026-02-15T20:26:10+03:00 DEBUG: VuFind\ILS\Driver\Folio: Token taken from global cache: eyJhbGciOiJIUzI1NiJ9.eyJzdWIiO... - DuChateau, Paul; Zachmann, David W. (Schaum's outline series, 2005)