Fereydooni, M., Sabaei, M., Dehghan, M., Babazadeh Eslamlou, G., & Rupp, M. (2018). Analytical Evaluation of Heterogeneous Cellular Networks Under Flexible User Association and Frequency Reuse. Computer Communications, 116, 147–158. https://doi.org/10.1016/j.comcom.2017.11.014