@inproceedings{aritonang_hidajati_2017, 
  title={The Improvement Effort in Evaluation Study Using Problem Based Learning on Hydrology Subject}, 
  DOI={10.2991/seadric-17.2017.49}, 
  publisher={Atlantis Press}, 
  author={Aritonang and Hidajati}, 
  year={2017}
  }