Topics in Functional EquationsTitu Andreescu, Iurie Boreico, Oleg Mushkarov, Nikolai Nikolov · First published 2012Open the Tome
Pokazatilite i kriteriite v sot͡s︡ialnoto upravlenieNikolaĭ Nikolov · First published 1988Open the Tome
Avtomobilen turizŭm, pŭtishta, kraĭpŭtni obektiNikolaĭ Petrov Nikolov · First published 1979Open the Tome
