Trends in citations to books on epidemiological and statistical methods in the biomedical literature.
Porta M, Vandenbroucke JP, Ioannidis JP, Sanz S, Fernandez E, Bhopal R, Morabia A, Victora C, Lopez T. PLoS One. 2013; 8(5):e61837. Epub 2013 May 7.