Chemical Constituents, Antibacterial Activity and Mode of Action of Elephant Ginger (Zingiber officinale var. officinale) and Emprit Ginger Rhizome (Zingiber officinale var. amarum) Essential Oils, Wibowo, Diki Prayugo, Mariani Ria, Hasanah Siti Uswatun, and Aulifa Diah Lia , Pharmacognosy Journal, March 2020, Volume 12, Issue 2, p.404-409, (2020)