1. The Art of scientific investigation;Beveridge,1961
2. Medical editors trial amnesty;Horton;Lancet,1997
3. Publication bias: the problem that won't go away;Dickersin;Ann NY Acad Sci,1993
4. Collected works of Francis Bacon;Bacon,1996
5. The Oxford Database of Perinatal Trials; developing a register of published reports of controlled trials;Chalmers;Control Clin Trials,1986