PMID 18435888. {{cite journal}}: |author= has generic name (help)CS1 maint: multiple names: authors list (link) ↑ Yerdel MA, Karayalcin K, Koyuncu A, Akin B, Koksoy C, Turkcapar AG, Erverdi N, Alaçayir I, Bumin C, Aras N (1999). "Direct trocar insertion versus veress needle insertion in laparoscopic cholecystectomy". The American Journal of Surgery.