Kleinschmidt, Jens MPI for Comparative and International Private Law, Max Planck Society;
https://max-eup2012.mpipriv.de/index.php/Authority_of_Agents (Any fulltext)
Kleinschmidt, J. (2012). Authority of Agents. In J. Basedow, K. J. Hopt, & R. Zimmermann (Eds.), The Max Planck Encyclopedia of European Private Law (pp. 88-93). Oxford: Oxford University Press.