Gaskin, J. F., Zhang, D. Y., and Bon, M. C. (2005). Invasion of Lepidium draba (Brassicaceae) in the western United States: distributions and origins of chloroplast DNA haplotypes. Molecular Ecology 14, 2331-2341.

Steel RGD, Torrie JH and Dicky DA (1997). “Principles and procedures of statistics: a  biometrical approach,” McGraw-Hill, New York New York, USA, pp: 400-428.

Weaver, S. E., and Riley, W. R. (1982). The Biology of Canadian Weeds.: 53. Convolvulus arvensis L. Canadian Journal of Plant Science 62, 461-472.

S.A.S. Institute. 2001. SAS/STAT software: Changes and enhancement through release 9.1. SAS Inst Cary NC.