N. Handayani and N. A. Saputra, “Persamaan Nilai Korelasi Indeks Plastisitas (PI) Tanah Dengan California Bearing Ratio (CBR) Tanah Lempung Palangka Raya: Equation of Correlation Value of Soil Plasticity Index (PI) and California Bearing Ratio (CBR) of Palangka Raya Clay”, n.a. ilm. teknik n.a., vol. 8, no. 1, pp. 63–71, Dec. 2019.