Studies composed by
Gunter Sonntag (Germany, 12.2.1945).
Some more information on Die Schwalbe and ChessComposerBlogspot.
Picture taken from Wikimedia.com.
(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) ).
Studies selected and one corrected by Peter Krug: