Graham, W., Brass, W., & Snow, R. W. (1988). Indirect estimation of maternal mortality: The sisterhood method. Centre for Population Studies, London School of Hygiene and Tropical Medicine.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Graham, Wendy, William Brass, و Robert W. Snow. Indirect Estimation of Maternal Mortality: The Sisterhood Method. London: Centre for Population Studies, London School of Hygiene and Tropical Medicine, 1988.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Graham, Wendy, et al. Indirect Estimation of Maternal Mortality: The Sisterhood Method. Centre for Population Studies, London School of Hygiene and Tropical Medicine, 1988.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.