Quartz sandstone peak forest landforms of Zhangjiajie Geopark, northwest Hunan Province, China: pattern, constraints and comparison. - Yang, Guifang; Tian, Mingzhong; Zhang, Xujiao; Chen, Zhenghong; Wray, Robert; Ge, Zhiliang; Ping, Yamin; Ni, Zhiyun; Yang, Zhen (Environmental Earth Sciences, 2012)