Cain VS, Johannes CB, Avis NE, Mohr B, Schocken M, Skurnick J, Ory M. Sexual functioning and practices in a multi-ethnic study of midlife women: baseline results from SWAN. J Sex Res. 2003 Aug 1;40(3):266-76.
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