Flora of the Pacific Northwest, Hitchcock and Cronquist, Univ. of Washington Press, 7th printing, 1990.
Glacier Park Native Plant Nursery Propagation Records, unpublished.
Seed Germination Theory and Practice, 2nd Edition, Deno, Norman, publ. 1993.
Seeding Rate Statistics for Native and Introduced Species, Hassell, Wendel, National Park Service and National Resources Conservation Service, April 1996.