Liu Y, Guo QH, Wieczorek J, Goodchild MF. Positioning localities based on spatial assertions. International Journal of Geographical Information Science [Internet]. 2009;23:1471-1501. 访问链接

Gong Y-X, Liu Y, Wu L, Xie Y-B. Boolean operations on conic polygons. Journal of Computer Science and Technology [Internet]. 2009;24:568-577. 访问链接

Zhang Y, Liu Y, Gao Y, Qi L, Song L. Extracting the international markets of a tourist destination from inlinks, in 2009 17th International Conference on Geoinformatics, Geoinformatics 2009.; 2009. 访问链接

Liu Y, Li R, Chen K, Yuan Y, Huang L, Yu H. KIDGS: A geographical knowledge-informed digital gazetteer service, in 2009 17th International Conference on Geoinformatics, Geoinformatics 2009.; 2009. 访问链接

Huang Q, Liu Y. On geo-social network services, in 2009 17th International Conference on Geoinformatics, Geoinformatics 2009.; 2009. 访问链接

Qi L, Zhang Y, Liu Y, Gao Y, Song L. Spatial distribution of the inlinks to the Beijing tourist attractions' websites, in 2009 17th International Conference on Geoinformatics, Geoinformatics 2009.; 2009. 访问链接

Jin X, Geng H, Gao Y, Liu Y. On vagueness of cardinal direction relationships in difference cognitive scenarios. Beijing Daxue Xuebao (Ziran Kexue Ban)/Acta Scientiarum Naturalium Universitatis Pekinensis [Internet]. 2009;45:1025-1032. 访问链接