Helen Dwight Reid Educational Foundation. (2003). Environment. Washington, DC: Heldref Publications.
استشهاد بنمط شيكاغوHelen Dwight Reid Educational Foundation. Environment. Washington, DC: Heldref Publications, 2003.
MLA استشهادHelen Dwight Reid Educational Foundation. Environment. Washington, DC: Heldref Publications, 2003.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.