Dose sparing of induction dose of propofol by fentanyl and butorphanol: A comparison based on entropy analysis oleh Jasleen Kaur, Moningi Srilata, Durga Padmaja, Ramchandran Gopinath, Sukhminder Jit Singh Bajwa, Dorairay John Kenneth, Parasa Sujay Kumar, Chalumuru Nitish, Wudaru Sreedhar Reddy