Nuraini S. FENOMENA HARD GROUND PADA BATU LEMPUNG KAYA GAMPINGAN FORMASI NANGGULAN, DI SUNGAI WATUPURU, PEGUNUNGAN KULON PROGO, YOGYAKARTA. Journal Technology of Civil, Electrical, Mechanical, Geology, Mining, and Urban Design [Internet]. 2019Jun.25 [cited 2024Dec.21];4(1):95-102. Available from: //journal.itny.ac.id/index.php/krvtk/article/view/1137