@article {Pljakov1989,
	title = {La r{\'e}gion de la Moyenne Struma aux VIIe{\textendash}IXe si{\`e}cles},
	journal = {Palaeobulgarica / Старобългаристика},
	volume = {13},
	year = {1989},
	pages = {100{\textendash}115},
	author = {Pljakov, Zdravko}
}
@article {Pljakov1988,
	title = {La r{\'e}gion de la Moyenne Struma durant le Moyen {\^a}ge bulgare},
	journal = {Palaeobulgarica / Старобългаристика},
	volume = {12},
	year = {1988},
	pages = {101{\textendash}114},
	author = {Pljakov, Zdravko}
}
@article {Pljakov1986,
	title = {La r{\'e}gion de la Moyenne Struma aux XIe{\textendash}XIIe si{\`e}cles},
	journal = {Palaeobulgarica / Старобългаристика},
	volume = {10},
	year = {1986},
	pages = {73{\textendash}85},
	author = {Pljakov, Zdravko}
}
