Michaels, Ralf MPI for Comparative and International Private Law, Max Planck Society;
https://scholarship.law.duke.edu/cgi/viewcontent.cgi?referer=&httpsredir=1&article=2694&context=faculty_scholarship (Any fulltext)
Michaels, R. (2009). Preamble I: Purposes, legal nature, and scope of the PICC; applicability by courts; use of the PICC for the purpose of interpretation and supplementation and as a model. In S. Vogenauer, & J. Kleinheisterkamp (Eds.), Commentary on the UNIDROIT principles of international commercial contracts (PICC) (pp. 21-80). Oxford: Oxford University Press.