Abel U, Koch A.The role of randomization in clinical studies: myths and beliefs. J Clin Epidemiol. 1999;52:487-497.
2.
Benson K, Hartz A, A comparison of observational studies and randomized, controlled trials. N Engl J Med. 2000;242:1878-1886.
3.
Byar DP, Simon RM, Friedewald WT, et al. Randomized clinical trials: perspectives on some recent ideas. N Engl J Med. 1976;295:74-80.
4.
Chalmers TC, Celano P, Sacks HS, Smith H Jr. Bias in treatment assignment in controlled clinical trials. N Engl J Med. 1983;309:1358-1361.
5.
Concato J, Shah N, Horwitz R.Randomized, controlled trials, observational studies, and the hierarchy of research designs. N Engl J Med. 2000;342,1887-1892.
6.
Feinstein AR. Current problems and future challenges in randomized clinical trials. Circulation. 1984;70:767-774.
7.
Horwitz RI, Viscoli CM, Clemens JD, Sadock RT. Developing improved observational methods for evaluating therapeutic effectiveness. Am J Med. 1990;89:630-638.
8.
Sacks H, Chalmers TC, Smith H Jr. Randomized versus historical controls for clinical trials. Am J Med. 1982;72:233-240.
9.
Schulz KF, Chalmers I, Hayes RJ, Altman DG. Empirical evidence of bias: dimensions of methodological quality associated with estimates of treatment effects in controlled trials. JAMA. 1995;273:408-412.
