SCHMID, W. George. En Encyclopedia of Shade Perennials. Portland: Timber Press, 2002. Dostupné online. ISBN0-88192-549-7. (anglicky)
ALLEN, Thomas J.; BROCK, Jim P.; GLASSBERG, Jeffrey. Caterpillars in the field and garden. A field guide to the butterfly caterpillars of North America. [s.l.]: Oxford University Press, 2005. Dostupné online. (anglicky)
MINEO, Baldassare. Rock garden plants. A color encyclopedia. Portland, Oregon: Timber Press, 1999. Dostupné online. ISBN0-88192-432-6. (anglicky)
CARTER, Susan; BECKER, Carrie; LILLY, Bob. Perennials. The gardener's reference. Portland, Oregon: Timber Press, 2007. Dostupné online. ISBN978-0-88192-820-4. (anglicky)