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2. Systematics, cytogenetics and evolution in Crepis;Babcock;Bot. Rev.,1942
3. The genus Crepis, I and II;Babcock;Univ. Calif. Publ. Bot.,1947
4. Chromosomes and phylogeny in Crepis. II. The relationships of 108 species;Babcock;Univ. Calif. Publ. Agr. Sci.,1934
5. Chromosomes and phylogeny in Crepis. III. The relationships of 113 species;Babcock;Univ. Calif. Publ. Bot.,1943