Bulgarian.Архивная копия от 3 марта 2016 на Wayback Machine Report on the Current Status of United Nations Romanization Systems for Geographical Names. Compiled by the UNGEGN Working Group on Romanization Systems. Version 4.0, February 2013.
Bulgarian.Архивная копия от 3 марта 2016 на Wayback Machine Report on the Current Status of United Nations Romanization Systems for Geographical Names. Compiled by the UNGEGN Working Group on Romanization Systems. Version 4.0, February 2013.