1. Ark, P. A. 1944. Personal communication.
2. Bonde, Reiner and Oscar L. Wyman. 1939. Bacterial wilt and soft rot of the potato. Me., Agr. Exp. Sta. Bul. 258.
3. Burkholder, W. H. 1938. The occurrence in the United States of the tuber ring rot and wilt of the potato (Phytomonas sepedonica) (Spiecker-tnann u. Kotthoff) Bergeyet al Amer. Potato Jour. 15: 243–245.
4. Güssow, H. T. and H. N. Racicot. 1940. Bacterial Ring Rot (Coloured chart). Dept. of Agriculture, Canada. (“The Canadian Department of Agriculture is prepared to supply free of charge a copy of the coloured chart on bacterial ring rot to all pathologists, inspectors, and potato certification agencies.”)
5. Iverson, V. E. and H. C. Kelly. 1940. Control of bacterial ring rot of potatoes with special reference to the ultraviolet-light method for selecting disease-free seed stock. Mont. Agr. Exp. Sta. Bul. 386: 1–15.