Some studies of 67 composed by Grandmaster
Paul Petrovic Keres
(Estonia, 7.1.1916 - 5.6.1975)
Paul Keres is a very famous chessplayer also writer of endgame books, so there is a lot information about him on the internet like on Wikipedia.
He was International Judge of the FIDE for chess compositions since 1957.
(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) ).