Lansing, J. B., & Morgan, J. N. (1971). Economic survey methods. Survey Research Center, University of Michigan].
Cita Chicago (17th ed.)Lansing, John B., i James N. Morgan. Economic Survey Methods. [Ann Arbor: Survey Research Center, University of Michigan], 1971.
Cita MLA (9th ed.)Lansing, John B., i James N. Morgan. Economic Survey Methods. Survey Research Center, University of Michigan], 1971.
Atenció: Aquestes cites poden no estar 100% correctes.