@misc
{TN_libero_mab2,
author = {
Gjuzelev, Vasil
},
title = {
The Bulgarian Kingdom in the 13th century: Trends and factors in its foreign policy
},
publisher = {National Library of Serbia},
isbn = {0584-9888},
isbn = {2406-0917},
keywords = {
General Arts and Humanities
},
year = {2009},
url = {
http://slubdd.de/katalog?TN_libero_mab2
}
}