Davis, J. L. (2009). The Northwest nature guide: Where to go and what to see month by month in Oregon, Washington, and British Columbia. Timber Press.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Davis, James L. The Northwest Nature Guide: Where to Go and What to See Month by Month in Oregon, Washington, and British Columbia. Portland, Or.: Timber Press, 2009.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Davis, James L. The Northwest Nature Guide: Where to Go and What to See Month by Month in Oregon, Washington, and British Columbia. Timber Press, 2009.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.