1. Dowson, W. J., 1957. Plant diseases due to bacteria. University Press, Cambridge.
2. Massey, L. M., 1950. Crown Gall. Am. Rose A. 35: 145–153.
3. Munnecke, D. E., Chandler, P. A. and Starr, M. P., 1963. Hairy root (Agrobacterium rhizogenes) of field roses. Phytopathology 53: 788–799.
4. Wormald, H., 1945. Physiologic races of the crown gall organism in Britain. Trans. Br. mycol. Soc. 28: 134–146.