@article {3516,
	title = {An Algebra for Structured Text Search and a Framework for Its Implementation},
	journal = {The Computer Journal},
	volume = {38},
	year = {1995},
	pages = {43--56},
	doi = {10.1093/comjnl/38.1.43},
	author = {Charles Clarke and Gordon Cormack and Forbes J. Burkowski}
}
