@article {3877,
	title = {On Type Systems for Object-Oriented Database Programming Languages},
	journal = {ACM Computing Surveys},
	volume = {34},
	year = {2002},
	pages = {409--449},
	doi = {10.1145/592642.592643},
	author = {Yuri Leontiev and Tamer Ozsu and Duane Szafron}
}
