@article{schöll_1999,  title={Nonlinear spatio-temporal dynamics in semiconductors},  volume={29},  ISSN={0103-9733},  url={https://doi.org/10.1590/S0103-97331999000400005},  DOI={10.1590/S0103-97331999000400005},  number={4},  journal={Brazilian Journal of Physics},  publisher={Sociedade Brasileira de Física},  author={Schöll, Eckehard},  year={1999},  month={Dec},  pages={627–638} }