Petrunkevitch 1955. Arachnida. Moore, R.C.[Ed]. Treatise on invertebrate paleontology. Part P. Arthropoda 2. Chelicerata with sections on Pycnogonida and Palaeoisopus., University of Kansas Press & the Geological Society of America, Lawrence, 1955: P42-P162. Chapter pagination: P42-P162