@phdthesis{oai:tsukuba.repo.nii.ac.jp:00009099,
 author = {Zheng, Xiao-Ping and 鄭, 小平},
 month = {},
 note = {1989, 【要旨】},
 school = {筑波大学, University of Tsukuba},
 title = {Economic analysis of the spatial structure of urban systems},
 year = {1990}
}