Halvorson, H. Orin 1897- Spores II; : a symposium held at Allerton Park, Illinois, October 22-23, 1960, under the auspices of the University of Illinois and with the support of the Office of Naval Research. [electronic resource] / Edited by H. Orin Halvorson.. — Minneapolis, : Burgess Pub. Co., [1961]. — ix, 296 p. : illus., diagrs., table. 23 cm.