Hazar, M., M. Beyleroglu, E. O. Tingaz, B. Gokyurek, and O. K. Esenturk. “A Comparison of Playfulness Levels of the Secondary Students in Kayseri and Trabzon Cities”. European Scientific Journal, ESJ, Vol. 13, no. 29, Oct. 2017, p. 58, doi:10.19044/esj.2017.v13n29p58.