Article Metrics
Abstract view : 1679 timesRefbacks
- There are currently no refbacks.
![Creative Commons License](https://i.creativecommons.org/l/by-nc-sa/4.0/88x31.png)
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Didik Mardiono
PT. Kaltim Prima Coal
Indonesia