Spurr, W. A. (1961). Business and economic statistics (Rev, [i.e. 2d].). Irwin.
Cita Chicago (17th ed.)Spurr, William Alfred. Business and Economic Statistics. Rev, [i.e. 2d]. Homewood, Illinois: Irwin, 1961.
Cita MLA (9th ed.)Spurr, William Alfred. Business and Economic Statistics. Rev, [i.e. 2d]. Irwin, 1961.
Atenció: Aquestes cites poden no estar 100% correctes.