These are the rules concerning transliteration in Bulgarian entries.
This system is based on the one adopted by the UNGEGN in 1977, the Bulgarian Council of Orthography and Transcription of Geographical Names in 1972, after the conventional scholarly system of transliteration used in linguistics.
Syllabic stress can be indicated by an acute accent (´) over the main component of the vowel: á, é, í, ó, ú, ǎ̀, já, jé, jó, jú (note that ̀ is used for ъ -ǎ̀).
Other common systems for Bulgarian are the Library of Congress system (ALA-LC), used in libraries and bibliographies, its simplified form found in the main text of many non-European publications, the British Standard used in British publications, BGN/PCGN in older atlases, ISO 9 and the recently promulgated Streamlined System. The last one was made mandatory for common use by Bulgaria in a law of 2009, and for official use by the UN in 2012, and by the USA and the United Kingdom in 2013.