Arnold, D. L., Arnold, Dawn L., Flegmann, A. W., Clarkson, J. M., "Development and Evaluation of a Laboratory‐Based Technique for Screening Somaclonal Regenerants of Watercress (Rorippanasturtium‐aquatium) for Resistance to Crook Root Disease (Spongospora subterranea f. sp. nasturtii)", Journal of Phytopathology, 1994