@phdthesis{oai:tsukuba.repo.nii.ac.jp:00008468,
 author = {ニヘイ, タカアキ and Nihei, Takaaki},
 month = {},
 note = {2000, Includes bibliographical references},
 school = {筑波大学, University of Tsukuba},
 title = {Temporal and spatial changes of agricultural regions in terms of the energy efficiency of crop production},
 year = {2001}
}