Research has to be with scholarly articles ex: ProQuest, gale academic one file, or university database. some link examples below:
https://search-proquest-com.ezproxy.libproxy.db.erau.edu/docview/209803731?pq-origsite=summon
https://search-proquest-com.ezproxy.libproxy.db.erau.edu/docview/899298609?pq-origsite=summon
https://go-gale-com.ezproxy.libproxy.db.erau.edu/ps/i.do?p=AONE&u=embry&id=GALE%7CA387231916&v=2.1&it=r&sid=summon