Classification and Checklist of the Leeches (Phylum Annelida: Class Clitellata: Subclass Hirudinida) occurring in North America north of Mexico

Dr. Roy T. Sawyer (Open Library) - Leech Museum

Encyclopedia of Life: Hirudo medicinalis - Medicinal Leech

BDELLANEA - Blogspot by Mark Siddall

Bloodsuckers - When modern medicine needs some help, surgeons call in mother nature's little helper. December 2001. Discover Magazine.

Animal Species: Leeches. Australian Museum.

Medicinal Leeches: Nature’s Finest Surgical Tool From the Swamps. Vol. 8, 2011. Yale Journal of Medicine & Law.