- Hafstad, G. E. 1958. Possible long distance spread of Dutch elm disease by transported beetles . Plant Disease Reporter 42:893-894.
- Hafstad, G. E., and W. C. Lueschow. 1961. Ceratocystis ulmi and zinc chloride experiment . Plant Disease Reporter 45:152.
- Hafstad, G. E., and J. F. Reynolds. 1961a. Effectiveness of dormant sprays in the control of Dutch elm disease . Arborist's News 26:81-82.
- Hafstad, G. E., and J. F. Reynolds. 1961b. Effectiveness of dormant sprays in the control of Dutch elm disease . Plant Disease Reporter 45:681.
- Worf, G. L., J. L. Libby, G. E. Hafstad, D. M. Norris, and E. B. Smalley. 1965. Fight Dutch elm disease. University of Wisconsin Agricultural Extension Service, Circular 600. 11 p.