Българска федерация по шахмат 1928
FIDE arbiters
FIDE tournaments
https://ratings.fide.com/rated_tournaments.phtml?country=BULperiod=current
Chess Results
Swiss-Manager
DGT
http://digitalgametechnology.com/
https://ratings.fide.com/rated_tournaments.phtml?country=BULperiod=current
http://digitalgametechnology.com/