Inheritance of Susceptibility to Infection by Helminthosporium Maydis Race 1 in Maze, Ullstrup, Arnold J. Reprinted from Journal of Agricultural Research, vol. 63, no. 6, September 15, 1941, pp. 331-334.
Two Physiologic Races of Helminthosporium Maydis in the Corn Belt, Ullstrup, Arnold J. Reprinted from Phytopathology, vol. XXXI, no. 6, June, 1941, pp. 508-521.