@book{71184,
	author = {Duvall, Wilbur I. and Aggson, James R. and United States},
	title = {Least squares calculation of horizontal stress from more than three diametral deformations in vertical boreholes},
	publisher = {Dept. of the Interior, Bureau of Mines},
	year = {1980 [i.e. 1979]},
	series = {Report of investigations},
	address = {[Washington]}
}