Freeman, H. J., & Freeman, K. J. (2000, January). Prevalence Rates and an Evaluation of Reported Risk Factors for Osteonecrosis (Avascular Necrosis) in Crohn’s Disease. Canadian Journal of Gastroenterology.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Freeman, Hugh J., و Katy J. Freeman. "Prevalence Rates and an Evaluation of Reported Risk Factors for Osteonecrosis (Avascular Necrosis) in Crohn’s Disease." Canadian Journal of Gastroenterology Jan. 2000.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Freeman, Hugh J., و Katy J. Freeman. "Prevalence Rates and an Evaluation of Reported Risk Factors for Osteonecrosis (Avascular Necrosis) in Crohn’s Disease." Canadian Journal of Gastroenterology, Jan. 2000.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.