Differentiation in a widely distributed, polytypic butterfly genus: five new subspecies of California Euphydryas (Lepidoptera: Nymphalidae). Emmel, Thomas C.[Ed]. Systematics of western North American butterflies., Mariposa Press, Gainesville, 1998: i-xviii, 1-878. Chapter pagination: 397-406. 399 [Zoological Record Volume 136]