The Karen villagers’ knowledge development in road construction: a case study of Panoki –Kopadoh (PNK) routeUba Sirikaew, Songklod Sae-Ueng, Somkiat Khwanpruk and Thanom SriworasaMATEC Web Conf., 192 (2018) 02058DOI: https://doi.org/10.1051/matecconf/201819202058