@article{bolstad_rule-based_1992,
	title = {Rule-based classification models:  flexible integration of satellite imagery and thematic spatial data},
	volume = {58},
	journal = {Photogrammetric Engineering and Remote Sensing},
	author = {Bolstad, P. V. and Lillesand, T.M.},
	year = {1992},
	keywords = {NTL}
}