Comparison of intraperitoneal and periportal bupivacaine and ropivacaine for postoperative pain relief in laparoscopic cholecystectomy: a randomized prospective study - Sharma, Chhavi S.; Singh, Manpreet; Rautela, Rajesh S.; Kochhar, Anjali; Adlakha, Nandita (Anaesthesia, Pain & Intensive Care, 2019)