Lusiantoro, L., and W. S. Ciptono. “An Alternative to Optimize the Indonesian’s Airport Network Design: An Application of Minimum Spanning Tree (MST) Technique”. Gadjah Mada International Journal of Business, Vol. 14, no. 3, Sept. 2012, pp. 267-02, https://jurnal.ugm.ac.id/v3/gamaijb/article/view/15372.