Zimmermann, Reinhard MPI for Comparative and International Private Law, Max Planck Society;
https://hwb-eup2009.mpipriv.de/index.php/Common_Frame_of_Reference (Any fulltext)
Zimmermann, R. (2009). Common Frame of Reference. In J. Basedow, K. J. Hopt, & R. Zimmermann (Eds.), Handwörterbuch des Europäischen Privatrechts (pp. 276-280). Tübingen: Mohr Siebeck.