Useful links:

• Penard, 1902: Faune Rhizopodique du Bassin du Léman
• Penard Collection in Geneva
• Leidy, 1879: Fresh-Water Rhizopods of North America
• Cash and Hopkinson, 1905: The British Freswater Rhizopoda and Heliozoa I
• Cash and Hopkinson, 1909: The British Freswater Rhizopoda and Heliozoa II
• Cash, Wailes and Hopkinson, 1915: The British Freswater Rhizopoda and Heliozoa III
• Cash, Wailes and Hopkinson, 1919: The British Freswater Rhizopoda and Heliozoa IV
• Cash, Wailes and Hopkinson, 1919: The British Freswater Rhizopoda and Heliozoa V
• Schaeffer, 1926 Taxonomy of the Amoebas
• Ehrenberg, 1930 Organisation, Systematik und geographisches Verhältniss der Infusionsthierchen
• Hertwig und Lesser, 1874: Ueber Rhizopoden und denselben nahestehende Organismen
• Biodiversity Heritage library, older papers and books, free downloads
• ISTAR International Society for Testate Amoeba Research
• International Code of Zoological Nomencalture 
• UNIEUK -Universal taxonomic framework and integrated reference gene databases for Eukaryotic biology, ecology, and evolution
• Acta Protozoologica - Free internet access to all papers
• Amoebae on the web, Alexey Smirnov
• Penard - The fascinating world of amoeboid organisms, Eckhard Voelcker and Steffen Clauss
• Photomicrographs, fascinating photomicrographs made by Norbert Hülsmann
• Plingfactory, Michael Plewka
• German Gallery, Wolfgang Bettighofer
• It came from the pond, Bruce Taylor
• Wonderful photomicrography, Charles Krebs
• Tiroler Mikrokosmos, Angie Opitz
• German microscopy, forum
• Microscopy-UK
• Photomicro- and macrography, forum
• MicrobeHunter
• Micam software
• Sea Plankton
• Tree of Life Web Project - Taxonomy
• Descriptions of Protists - Nies, Japanese site
• Julia Török
• Amöben, German site
• Dutch Gallery, Wim van Egmond
• Protists & Prokaryotes, John S. Douglas