===Papers===* Papers, 1939-1970 Collected papers of Karl August Wittfogel (1939-1970) University of Washington Libraries* Register of Karl Wittfogel Papers Hoover Institution==External links==* Columbia Encyclopedia Wittfogel (one paragraph) article* Wittfogel entry of the Personenlexikon Internationale Beziehungen virtuell of the TU Braunschweig (Ulrich Menzel)* Wittfogel, Karl August 1896-1988 (WorldCat Identity Page)==Notes & References==
* Карл Август Виттфогель в Литературной энциклопедии* Columbia Encyclopedia Wittfogel (one paragraph) article* Wittfogel entry of the Personenlexikon Internationale Beziehungen virtuell of the TU Braunschweig (Ulrich Menzel), in German ]* Wittfogel, Karl August 1896—1988 (WorldCat Identity Page)