Nelson,Michael. (1990). The Presidency and the political system. Washington: Congressional Quarterly.
استشهاد بنمط شيكاغوNelson,Michael. The Presidency and the Political System. Washington: Congressional Quarterly, 1990.
MLA استشهادNelson,Michael. The Presidency and the Political System. Washington: Congressional Quarterly, 1990.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.