Shafer, C. (1985). Excellence in teaching with the seven laws: A contemporary abridgment of Gregory's seven laws of teaching. Baker.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Shafer, Carl. Excellence in Teaching with the Seven Laws: A Contemporary Abridgment of Gregory's Seven Laws of Teaching. Grand Rapids: Baker, 1985.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Shafer, Carl. Excellence in Teaching with the Seven Laws: A Contemporary Abridgment of Gregory's Seven Laws of Teaching. Baker, 1985.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.