III Borate Conference “Sofia’99”
September 1999 - Sofia
XIV Scientific Conference on Glass and Ceramics
September 2002 – Varna
II Balkan Conference on Glass Science and Technology
September 2002 - Varna
XV Scientific Conference on Glass and Ceramics
September 2005 – Varna
III Balkan Conference on Glass Science and Technology
September 2005 - Varna
XVI Scientific Conference on Glass and Ceramics
September 2008 – Varna
IV Balkan Conference on Glass Science and Technology
September 2008 – Varna
XVII Scientific Conference on Glass and Ceramics
September 2011 – Nessebar
V Balkan Conference on Glass Science and Technology
September 2011 – Nessebar