1. Dobell C. Antony van Leeuwenhoek and His Little Animals. Dover Publications, New York 1960; 111, (This is an unabridged reprint of the 1932 edition which honored the 300th anniversary of Leeuwenhoek's birth.)
2. Dobell C. Antony van Leeuwenhoek and His Little Animals. Dover Publications, New York 1960; 133
3. Ehrenberg C. G. Die Infusionsthierschen als vollkommene Organismen. Leipzig 1838; 15