@article{article400,
  title = {Vibrational Analysis and Hydrogen-Bonding Effects on the Vibrational Modes of Zwitterionic DL-Tryptophan: IR Spectroscopy and DFT Calculations},
  author = {BOUKAOUD, A. and CHIBA, Y. and DEHBAOUI, M. and GUECHI, N.},
  journal = {Sigma Journal of Engineering and Natural Sciences},
  year = {2019},
  volume = {37},
  pages = {1181-1198},
  doi = {}
}