2021. Combination of olanzapine with bispectral index guided anesthesia to prevent postoperative delirium in elderly patients undergoing major gastrointestinal elective surgery: a randomized, double-blind, placebo-controlled study protocol. Principles and Practice of Clinical Research. 7, 3 (Nov. 2021), 35–42. DOI:https://doi.org/10.21801/ppcrj.2021.73.5.