Sinauer Associates, Inc., Sunderland. Campbell, Neil A. 1996. Carson, R. 1980. The Royal Ontario Museum, Toronto. Cary, S.C., Shank, T. and Stein, J. 1998.
Worms bask in extreme temperatures.
Chapelle, G. and Peck, L.S. 1999. Polar gigantism dictated by oxygen availability. Dales, R.P. 1967. Hutchinson and Co., Ltd., London. Emig, C.C. 1997.