The cost of surgical training: analysis of operative time for laparoscopic cholecystectomy

Strauss Und Torney M., Dell-Kuster S., Mechera R., Rosenthal R., Langer I. (2012):
2012 Sep;26(9):2579-86. doi: 10.1007/s00464-012-2236-1. Epub 2012 Apr 5.

https://www.ncbi.nlm.nih.gov/pubmed/22476835