1. Trend of diabetic admissions in Tikur Anbessa and St. Paul's University Teaching Hospitals from January 2005-December 2009, Addis Ababa, Ethiopia;Adem A;Ethiopian medical journal,2011
2. Amin P.M.,hajizadeh E.,Moghimi B,D.,safaee A,,and abadi A.,Reza M.Z.(2007) comparing cox regression and parametric models for survival of patients with gastric carcinoma. Asian pacific journal of cancer prevention, 8, pp. 412–416.
3. Bradburn, M.J., Clark, T.G., Love, S.B. and Altman, D.G., 2003. Survival analysis part II: multivariate data analysis–an introduction to concepts and methods. British journal of cancer, 89(3), p.431.
4. Collett, D., 2003. Modelling survival data in medical research(No. 610.72 C721m). Florida, US: CRC Press.
5. Regression models and life-tables;Cox DR;Journal of the Royal Statistical Society: Series B (Methodological),1972