Borsari L, Malagoli C, Werler MM, Rothman KJ, Malavolti M, Rodolfi R, De Girolamo G, Nicolini F, Vinceti M. Joint effect of maternal tobacco smoking and pregestational diabetes on preterm births and congenital anomalies: a population-based study in northern Italy. J Diabetes Res. 2018 Jun 28. doi: 10.1155/2018/2782741
Williams VSL. The "unbiased" anchor: bridging the gap between DIF and item bias. Appl Meas Educ. 1997;10(3):253-67. doi: 10.1207/s15324818ame1003_4