@article{Zumbo2007,
author = {Zumbo, B.D. and Gadermann, A.M. and Zeisser, C.},
title= {Ordinal versions of coefficients alpha and theta for Likert Rating Scales},
year = {2007},
doi = {10.22237/jmasm/1177992180},
volume = {6},
number = {1},
pages = {21--29},
}