Não informado. (1966). Index to selected outdoor recreation literature. U.S. Department of the Interior, Bureau of Outdoor Recreation.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Não informado. Index to Selected Outdoor Recreation Literature. Washington: U.S. Department of the Interior, Bureau of Outdoor Recreation, 1966.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Não informado. Index to Selected Outdoor Recreation Literature. U.S. Department of the Interior, Bureau of Outdoor Recreation, 1966.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.