Name variants: Petkov, Petko D. (preferred) Content type - Any - Article Book Chapter Items per page 5102550100 Sort by Title (ascending)Title (descending)Oldest firstNewest first Displaying 1 - 1 of 1. Article Iliev, Ivan G.; Petkov, Petko D.. An unknown model for constructing the negative imperative in Bulgarian. Opera Slavica. 2018, vol. 28, iss. 2, pp. 39–44.