Understanding proboscidean evolution: a formidable task Je-heskel Shoshani(1998)
International Commission on Stratigraphy charts(2019)
Advances in Elephant Phylogony(2004)
A proboscidean from the late Oligocene of Eritrea, a ‘‘missing link’’ between early Elephantiformes and Elephantimorpha, and biogeographic implications (2006)
The latest woolly mammoths (2002)
The evolution of elephants, by Jan van der Made (2010)