@inproceedings{sgem2018S14072,
  title = {SUSTAINABILITY PHENOMENA IN STRATEGIES OF ESTONIAN LANGUAGE FOR 2017-2020 AND FOREIGN LANGUAGES FOR 2009-2015},
  author = {L. Roostalu and M. Vahter},
  booktitle = {5th International Multidisciplinary Scientific Conference on Social Sciences and Arts SGEM 2018},
  year = {2018},
  pages = {555-562},
  publisher = {STEF92 Technology},
  doi = {10.5593/sgemsocial2018/3.6/S14.072}
}