Suhartana, Sona, and Yuniawati. 2019. “RIL Skidding Techniques to Improve Productivity and Minimize Production Cost and Environmental Damage (A Case Study at PT Inhutani II Malinau)”. Jurnal Penelitian Kehutanan Wallacea 8 (2):113-23. https://doi.org/10.18330/jwallacea.2019.vol8iss2pp113-123.