Lukowski SL, DiTrapani J, Rockwood NJ, Jeon M, Thompson LA, Petrill SA. Etiological distinction across dimensions of math anxiety. Behav Genet. 2019 May;49(3):310-6. doi: 10.1007/s10519-018-09946-3
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