Groves, R. M., Fowler, F. J., Couper, M. P., Lepkowski, J. M., Singer, E., & Tourangeau, R. (2009). Survey methodology (2a. ed.). John Wiley and Sons.
Cita Chicago (17th ed.)Groves, Robert M., Floyd J. Fowler, Mick P. Couper, James M. Lepkowski, Eleanor Singer, i Roger Tourangeau. Survey Methodology. 2a. ed. John Wiley and Sons, 2009.
Cita MLA (9th ed.)Groves, Robert M., et al. Survey Methodology. 2a. ed. John Wiley and Sons, 2009.
Atenció: Aquestes cites poden no estar 100% correctes.