Zimmermann, Reinhard MPI for Comparative and International Private Law, Max Planck Society;
https://max-eup2012.mpipriv.de/index.php/Common_Frame_of_Reference_(CFR) (Any fulltext)
Zimmermann, R. (2012). Common Frame of Reference. In J. Basedow, K. J. Hopt, & R. Zimmermann (Eds.), The Max Planck Encyclopedia of European Private Law (pp. 261-265). Oxford: Oxford University Press.