https://historica.unibo.it/entities/publication/251c0611-9142-4ce1-8e28-5a5167357e08
Trapezitsa (fortress), Veliko Tarnovo
fortressveliko
https://historica.unibo.it/entities/publication/4cd8d71f-bd32-46d1-a911-8e9143f6d51e
Trapezitsa (fortress), Veliko Tarnovo
fortressveliko