http://energostal.kharkov.ua/content/documents/21/2061/Attaches/lpovidomlennya_fosfor_2018.pdf
http://energostal.kharkov.ua/content/documents/21/2061/Attaches/titul_ukr.pdf
http://energostal.kharkov.ua/content/documents/21/2061/Attaches/fosfor_1_redaktsiya.pdf
http://energostal.kharkov.ua/content/documents/21/2061/Attaches/fosfor_poyasn.zapis.pdf