Dietrich, W., & Cunningham, B. (2003). Natural grace: The charm, wonder, and lessons of Pacific Northwest animals and plants. University of Washington Press.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Dietrich, William, و Brenda Cunningham. Natural Grace: The Charm, Wonder, and Lessons of Pacific Northwest Animals and Plants. Seattle, Washington ; London, England: University of Washington Press, 2003.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Dietrich, William, و Brenda Cunningham. Natural Grace: The Charm, Wonder, and Lessons of Pacific Northwest Animals and Plants. University of Washington Press, 2003.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.