Davey, J. W., P. C. Gugiu, and C. L. S. Coryn. “Quantitative Methods for Estimating the Reliability of Qualitative Data”. Journal of MultiDisciplinary Evaluation, vol. 6, no. 13, Feb. 2010, pp. 140-62, https://journals.sfu.ca/jmde/index.php/jmde_1/article/view/266.