CZARNECKI, David B. 1994 The freshwater diatom culture collection at Loras College, Dubuque, Iowa Proc. Int. Diatom Symp. 11 [Mem. Calif. Acad. Sci. 17]: 155-173, 1 table [incl. n.c. in Achnanthidium, Craticula, Encyonema, Fragilariforma, & Sellaphora]