Husaini, F., and Dewi Shinta Wulandari Lubis. “The Role Of Supervisors And Standard Operating Procedures For Cleaning Rooms In Improving The Performance Of Employees Housekeeping Department Hotel Grand Mercure Medan”. Jurnal Ekonomi, vol. 13, no. 02, June 2024, pp. 1316-28, https://ejournal.seaninstitute.or.id/index.php/Ekonomi/article/view/4643.