@book{132967,
	author = {Wrightsman, Lawrence Samuel, joint author.},
	title = {Métodos de investigación en las relaciones sociales},
	publisher = {Ediciones Rialp},
	year = {1980.},
	address = {Madrid},
	edition = {9a ed. totalmente renovada y ampliada.},
	note = {Includes index.}
}