Microbial Characteristics of Lower Respiratory Tract Infections in Patients Referred from Primary Care Hospitals oleh Thanh Nguyen-Van, Van Pham-Hung, Ngoc Tran-Van, Duy Nguyen-Dinh, Thuy Cao-Thi-My, Huong Le-Thi-Thu, Thu Vo-Pham-Minh, Phu Tran-Nguyen Trong, Van Duong-Thi-Thanh