Relativity: the special and the general theory; a popular exposition 2026-02-15T22:33:02+03:00 DEBUG: VuFind\ILS\Driver\Folio: Token taken from global cache: eyJhbGciOiJIUzI1NiJ9.eyJzdWIiO... - Einstein, Albert, 1879-1955 (Bonanza paperback, 1961)