Selection of studies composed by
Nicolai Dimitrievitch Grigoriev
(Russia, 14.8.1895 - 10.11.1938).
More information about him at: Wikipedia, Chess.com and ChessPro.ru
(All his studies, more exact dates, possible corrections or cooks and exact details about sources can be found in the
Harold van der Heijden database V (31-12-2015) a collection with over 85.000 studies)