https://bulgarianhistory.org/asen-zlatarov-v-slujba-na-choveka/?fbclid=IwAR2CjIbWPYu7-SAmkbzyNCqkeYspa2VpSvWvhoLxsz5P9VTNJaQm_xmiXUU
https://ezikovavt.com/%D1%83%D1%87%D0%B8%D0%BB%D0%B8%D1%89%D0%B5/%D0%B7%D0%B0-%D0%BD%D0%B0%D1%81/%D0%B7%D0%B0-%D0%B0%D1%81%D0%B5%D0%BD-%D0%B7%D0%BB%D0%B0%D1%82%D0%B0%D1%80%D0%BE%D0%B2/?fbclid=IwAR3I4Q5w_svxrOG4B38-gPqEmc1ZjKsw45dE3qQlXGPDhWLKnYXCgPo-bYA
https://bg.wikipedia.org/wiki/%D0%90%D1%81%D0%B5%D0%BD_%D0%97%D0%BB%D0%B0%D1%82%D0%B0%D1%80%D0%BE%D0%B2
https://www.14su.bg/%D1%83%D1%87%D0%B8%D0%BB%D0%B8%D1%89%D0%B5%D1%82%D0%BE/%D0%B1%D0%B8%D0%BE%D0%B3%D1%80%D0%B0%D1%84%D0%B8%D1%8F-%D0%BD%D0%B0-%D0%B0%D1%81%D0%B5%D0%BD-%D0%B7%D0%BB%D0%B0%D1%82%D0%B0%D1%80%D0%BE%D0%B2/