1. Testing for causality and prognosis: etiological and prognostic models;G Tripepi;Kidney Int,2008
2. Confounding: What it is and how to deal with it;KJ Jager;Kidney Int,2007
3. An overview of the objectives of and the approaches to propensity score analyses;G Heinze;Eur Heart J,2011
4. Vittinghoff E, Glidden DV, Shiboski SC, McCulloch CE (2004) Regression methods in biostatistics - Linear, logistic, survival, and repeated measures models. Springer-Verlag. 340 p. (Chapter 5.5.3.).
5. Royston P, Sauerbrei W (2008) Multivariable model-building. A pragmatic approach to regression analysis based on fractional polynomials for modelling continuous variables. Chichester: John Wiley & Sons, Ltd. 322 p.