Hello Shary, Here are those 2 references regarding second-level analyses: Holmes A, Friston K. 1998. Generalisability, random effects and population inference. NeuroImage 7: S754 Friston KJ, Stephan KE, Lund TE, Morcom A, Kiebel S. 2005. Mixed-effects and fMRI studies. Neuroimage 24: 244-52 Eric