Strickler, D. (1997). Northwest penstemons: 80 species of Penstemon native to the Pacific Northwest. Flower Press.
Цитирование в стиле Чикаго (17-е изд.)Strickler, Dee. Northwest Penstemons: 80 Species of Penstemon Native to the Pacific Northwest. Columbia Falls, Mont.: Flower Press, 1997.
Цитирование MLA (8-е изд.)Strickler, Dee. Northwest Penstemons: 80 Species of Penstemon Native to the Pacific Northwest. Flower Press, 1997.
Предупреждение: эти цитированмия не могут быть всегда правильны на 100%.