Ellger, Reinhard MPI for Comparative and International Private Law, Max Planck Society;
https://max-eup2012.mpipriv.de/index.php/Prohibition_of_Restrictive_Agreements_and_Exemptions (Any fulltext)
Ellger, R. (2012). Prohibition of Restrictive Agreements and Exemptions. In J. Basedow, K. J. Hopt, & R. Zimmermann (Eds.), The Max Planck Encyclopedia of European Private Law (pp. 1361-1366). Oxford: Oxford University Press.