He developed players like Stefan Bogomilov , Bozhil Kolev , Stefan Yanev , Damyan Georgiev , Ivan Derventski , Spas Kirov , Nedko Nedev . He developed players like Stefan Bogomilov , Bozhil Kolev , Stefan Janev , Damyan Georgiev , Ivan Derventski , Spas Kirov , Nedko Nedev .