1. Department of Gerontology, The First Hospital of Qiqihar, Qiqihar, Heilongjiang, China
2. Department of Gerontology, Affiliated Qiqihar Hospital, Southern Medical University, Qiqihar, Heilongjiang, China
3. Department of Library, The First Hospital of Qiqihar, Qiqihar, Heilongjiang, China
4. Department of Library, Affiliated Qiqihar Hospital, Southern Medical University, Qiqihar, Heilongjiang, China