1. Anikster, Y., Bushnell, W. R., Eilam, T., Manisterski, J., & Roelfs, A. P. (1997). Puccinia recondita causing leaf rust on cultivated wheats, wild wheats, and rye. Canadian Journal of Botany, 75, 2082–2096.
2. Anonymous. (1998). Descriptive list of recommended varieties for cereals, maize, oil and fiber crops, legumes, beet and intermediate crops [In German]. Hannover: Strothe Verlag.
3. Anonymous. (2001). Descriptive list of recommended varieties for cereals, maize, oil and fiber crops, legumes, beet and intermediate crops [In German]. Hannover: Strothe Verlag.
4. Bayles, R. A., Flath, K., Hovmøller, M. S., & de Vallavielle-Pope, C. (2000). Breakdown of the Yr17 resistance to yellow rust of wheat in Northern Europe. Agronomie, 20, 805–811.
5. Böker, F. (2010): Analyse mehrdimensionaler Daten. Vorlesungsskript Universität Göttingen, Institut für Statistik und Ökonometrie. Internet resource: http://www.statoek.wiso.uni-goettingen.de/cms/user/index.php?lang=de§ion=teaching.ws2009.multivariate.notizen , (verified May 12, 2011).