@article{Fister2013Modified,
  title={Modified firefly algorithm using quaternion representation},
  author={Fister, Iztok and Yang, Xin-She and Brest, Janez, Fister Jr., Iztok},
  journal={Expert Systems with Applications},
  volume={40},
  number={18},
  pages={7220--7230},
  year={2013},
  publisher={Elsevier}
}