Recommendations for examining and interpreting funnel plot asymmetry in meta-analyses of randomised controlled trials

Jonathan A C Sterne, Alex J. Sutton, John P A Ioannidis, Norma Terrin, David R. Jones, Joseph Lau, James Carpenter, Gerta Rücker, Roger M. Harbord, Christopher H. Schmid, Jennifer Tetzlaff, Jonathan J. Deeks, Jaime Peters, Petra Macaskill, Guido Schwarzer, Sue Duval, Douglas G. Altman, David Moher, Julian P T Higgins