Rotua Nainggolan, F.M. et al. 2021. The Value of Gotong-royong in the Mountainous Settlement of Kepuharjo Village at Pagerjurang Permanent Shelter in Yogyakarta, Indonesia. International Journal of Built Environment and Sustainability. 8, 3 (Aug. 2021), 93–106. DOI:https://doi.org/10.11113/ijbes.v8.n3.822.