Chemical Diversity of Essential Oils from Aerial Parts of Eight Species of Zingiberaceae Family from Vietnam oleh Hong Thien Van, Sao Mai Dam, Uyen Thuy Xuan Phan, Thi Ngoc Anh Nguyen, Thi Bao Tran Nguyen, Tan Loc Tran, Thao Nguyen Luu, Van Son Le, Nguyen Tuong An Huynh