Riga 1926 (2-21 November) First Riga Championship. <Petrovs finished 1st>, over T. Bergs, F. Apsenieks, and others, scoring +5-0=3. Fride pp.3-4; Gino Di Felice, "Chess Results 1921-1930" (McFarland,2006), p.149; "Pirmadiena", Nr.90, November 22, 1926, p.3; "Brīvā Tēvija", November 23, 1926, p.4