S. I.  Warwick and Al-Shehbaz, I. A., ?Nomenclatural notes on Sisymbrium (Brassicaceae)?, Novon, vol. 13, pp. 265 - 267, 2003.

S. I.  Warwick, ?Rapistrum?, in Flora of North America, vol. 7, Oxford University Press, 2010, pp. 440 - 441.

S. I.  Warwick, ?Erucastrum?, in Flora of North America, vol. 7, Oxford University Press, 2010, pp. 435 - 436.

S. I.  Warwick, ?B) Hirschfeldia?, in Flora of North America, vol. 7, Oxford University Press, 2010, pp. 436 - 437.

S. I.  Warwick and Wall, D. A., ?The biology of Canadian weeds. 108. Erucastrum gallicum (Willd.) O.E. Schulz.?, Canad. J. Pl. Sci., vol. 78, no. 1, pp. 155 - 165, 1998.

S. I.  Warwick and Sauder, C. A., ?Phylogeny of tribe Brassiceae (Brassicaceae) based on chloroplast restriction site polymorphisms and nuclear ribosomal internal transcribed spacer and chloroplast trnL intron sequences?, Canadian Journal of Botany, vol. 83, no. 5, pp. 467 - 483, 2005.

S. I.  Warwick and Black, L. D., ?Molecular relationships in subtribe Brassicinae (Cruciferae, tribe Brassiceae)?, Can. J. Bot, vol. 71, pp. 906 - 918, 1993.