Pinus ponderosa: A checkered past obscured four species.
Willyard A, Gernandt DS, Potter K, Hipkins V, Marquardt P, Mahalovich MF, Langer SK, Telewski FW, Cooper B, Douglas C, Finch K, Karemera HH, Lefler J, Lea P, Wofford A. Pinus ponderosa: A checkered past obscured four species. Am J Bot. 2017 Jan; 104(1):161-181.