I. Wijesinghe and C. Kumarasinghe, “Relationship Among the Diameter of the Area of Influence & Refill Usage of Sri Lanka Using Anonymized Call Detail Records”, EAI Endorsed Scal Inf Syst, vol. 4, no. 12, p. e5, Jan. 2017, doi: 10.4108/eai.18-1-2017.152104.