@article{chen76er,
	title = {The Entity-Relationship Model - Toward a Unified View of Data},
	author = {Peter Pin-Shan Chen},
	journal = {ACM Trans. Database Syst.},
	number = {1},
	pages = {9-36},
	url = {http://dx.doi.org/10.1145/320434.320440},
	volume = {1},
	year = {1976},
	biburl = {http://www.bibsonomy.org/bibtex/2ff96d52c195563a280d57b6b3092c3fb/sb3000},
	keywords = {database modelling seminal }
}