Books   Haworthia Revisited, A Revision of the Genus – Bruce Bayer, 1999         Haworthia Update - Essays on Haworthia - Volume 1 - Bruce Bayer, 2002         Haworthia Photographs used to typify taxa desribed by Dr. Karl von Poellnitz – Ingo Breuer, 1999         Notes on Haworthias, J.R. Brown ; 1st edition 1999 published by Ingo Breuer and Arbeitsfreis für Mammillarienfreunde e.V., 1999         The World of Haworthias, Volume 1 and 2 – Ingo Breuer         Haworthia Hand Book - Volume 1 and 2 - Tony Sato, 1993 and 1995. Photo booklets devoted to truncata and maughanii, published by the Japan Cactus Planning Co. Press.         The Genus Haworthia, A Taxonomic revision – Charles L. Scott, 1985         Haworthia and Astroloba, A Collector’s Guide – John Pilbeam, 1983         The New Haworthia Handbook – Bruce Bayer, 1982         Gasterias of South Africa - A new revision of a major succulent group - E.J.van Jaarsveld, 1994 Periodicals   Haworthiad. Periodical from the Haworthia Society (UK)         Aloe. Periodical from the Succulent Society of South Africa.         Alsterworthia International. Periodical published by Harry Mays from beginning of 2001.         Haworthia Study . Periodical published by the Haworthia Society of Japan. In Japanese with some translation into English. Great photos ! The must in haworthia breeding and selection. Subscription is possible via Alsterworthia International. (2 journals/year)