APA (7th ed.) Citation

Smit, R., & Engeli, E. (2015). An empirical model of mixed-age teaching. International Journal of Educational Research, 74, 136. https://doi.org/10.1016/j.ijer.2015.05.004

Chicago Style (17th ed.) Citation

Smit, Robbert, and Eva Engeli. "An Empirical Model of Mixed-age Teaching." International Journal of Educational Research 74 (2015): 136. https://doi.org/10.1016/j.ijer.2015.05.004.

MLA (9th ed.) Citation

Smit, Robbert, and Eva Engeli. "An Empirical Model of Mixed-age Teaching." International Journal of Educational Research, vol. 74, 2015, p. 136, https://doi.org/10.1016/j.ijer.2015.05.004.