Arno, S. F., & Hammerly, R. P. (2007). Northwest trees: Identifying and understanding the region's native trees (Anniversary ed., rev. ed.). Mountaineers Books.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Arno, Stephen F., و Ramona P. Hammerly. Northwest Trees: Identifying and Understanding the Region's Native Trees. Anniversary ed., rev. ed. Seattle, WA: Mountaineers Books, 2007.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Arno, Stephen F., و Ramona P. Hammerly. Northwest Trees: Identifying and Understanding the Region's Native Trees. Anniversary ed., rev. ed. Mountaineers Books, 2007.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.