Hi Hidde,
I found these in "The Imperial Russian Air Service - Famous Pilots and Aircraft of World War I" by Alan Durkota, Thomas Darcey and Victor Kulikov.
Dux built Nieuport 16 of the First Fighter Detachment-winter 1916-19
Grigorovich M-15
Morane-Saulnier I of the 4th Corps Dedachment-winter 1915
Morane-Saulnier-L
Morane-Saunier I of the 4th Corps Detachment-winter 1915
Nieuport 14
Nieuport 21
Nieuport 21 1825 12th Fighte Detachment - winter1917-Jaan M Mahlapuu
Nieuport 21 in flight
Sikorsy-S-16
I hope this helps
Willem van Berkel from Holland