The conservation biology of tortoises /
Swingland, Ian R.(Ian Richard),1946-
Klemens, Michael W.
Tortoise and Freshwater Turtle Specialist Group (International Union for Conservation of Nature and Natural Resources)
Gland : International Union for Conservation of Nature and Natural Resources,
1989.
The results of "Operation tortoise" a worldwide project conducted by the IUCN/SSC Tortoise and Freshwater Turtle Specialist Group
Turtles.