@article {Liu2004271,
	title = {UML-G: an object-oriented modeling language for geographical information applications},
	journal = {Beijing Daxue Xuebao (Ziran Kexue Ban)/Acta Scientiarum Naturalium Universitatis Pekinensis},
	volume = {40},
	number = {2},
	year = {2004},
	note = {施引文献 3},
	pages = {271},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-2542632692\&partnerID=40\&md5=7ce93611bbbbbc09766f0ac57b409d90},
	author = {Y. Liu and Lin, B. and Tang, D.}
}
