Elementary differential equations and boundary value problems 2026-02-15T17:34:08+03:00 DEBUG: VuFind\ILS\Driver\Folio: Token taken from global cache: eyJhbGciOiJIUzI1NiJ9.eyJzdWIiO... - Boyce, William E.; DiPrima, Richard C. (J. Wiley, 1997)