1. Cytogenetic studies in Poa pratensis and its hybrid with Poa alpina;Åkerberg;Hereditas,1942
2. Clausen , J. D. D. Keck W. M. Hiesey 1940 Experimental studies on the nature of species. I. Effect of varied environments on western North American plants Carnegie Inst. Washington Publ. 520
3. Experimental taxonomy;Clausen;Carnegie Inst. Washington Year Book,1947
4. Clausen , J. D. D. Keck W. M. Hiesey 1948 Experimental studies on the nature of species. III. Environmental responses of climatic races of Achillea Carnegie Inst. Washington Publ. 581
5. Chromosome numbers in Poa, Agropyron, and Elymus;Hartung;Amer. Jour. Bot.,1946