1. Bawden, F. C. 1934. Studies on a virus causing foliar necrosis of the potato. Roy. Soc. London Proc., Bull. 116: 375–394.
2. Cockerham, G. 1939. The distribution and significance of certain potato viruses in Scotland. Scottish Jour. Agr. 22: 1–11.
3. —. 1943. The reaction of potato varieties to viruses X, A, B and C. Ann. Appl. Biol. 30: 338–344.
4. Cockerham, G. 1949. Potato virus diseases, Scottish Society for Research in Plant Breeding, Report Ann. Meet. Pp. 19–22.
5. Darby, J. F., R. H. Larson and J. C. Walker. 1951. Variation in virulence and properties of potato virus Y strains. Wis. Agr. Exp. Sta. Res. Bull. 177. 1–30.