Information on <Leonids Dreibergs> from <hemy> here: Vladimir Petrov (kibitz #929)
Interesting article was published by Tenis Melngailis in "Brīvā Zeme", April 1, 1940, p. 11: "Jaunie Rīgas šacha meistari" - "New Riga chess champion". (In this case 'meistar' should be translated as a 'champion', not as a 'master').
"2 rounds before the end of the tournament is already known the name of the winner - 32 years old Leonids Dreibergs. Indeed impressive result. This time the winner was the strongest in spirit and body.
Success of chess player depends on health, well-being. Rarely, another game requires a nervous effort, energy consumption like a chess. It should not be forgotten that none of the chess players has economic security, except, perhaps, Koblenc. Everyone is working, earns his daily bread.
These daily worries do not require less energy.
And in the spring, a person feels a lot of fatigue. For this very reason, I did not participated in this tournament.
Grand master V. Petrov, as well as K. Ozols are busy to finish the University, so they did not played too..."