Links
[1] https://www.protergia.gr/el/content/media-kit-%CE%BB%CE%BF%CE%B3%CF%8C%CF%84%CF%85%CF%80%CE%B1
[2] https://www.protergia.gr/el/content/media-kit-%CE%AD%CE%BD%CF%84%CF%85%CF%80%CE%B1
[3] https://www.protergia.gr/sites/default/files/PR_Brochure_19x27cm_greek_2017_new.pdf
[4] https://www.protergia.gr/sites/default/files/pr_brochure_19x27cm_greek_march_2018.pdf