Schmidt, Jan Peter MPI for Comparative and International Private Law, Max Planck Society;
https://hwb-eup2009.mpipriv.de/index.php/Rechtsgesch%C3%A4ft (Any fulltext)
Schmidt, J. P. (2009). Rechtsgeschäft. In J. Basedow, K. J. Hopt, & R. Zimmermann (Eds.), Handwörterbuch des Europäischen Privatrechts (pp. 1241-1245). Tübingen: Mohr Siebeck.