Complex sentence: During this time, he cooperates with Izydor Gulgowski, Friedrich Lorentz, and the German "Verein für Kaschubische Volkskunde" (Society for Kashubian Folk Studies) while studying the folklore of the region, he did not forsake publishing in "Gazeta Gdańska".
Split into simpler sentences: During this time, he cooperated with Izydor Gulgowski, Friedrich Lorentz, and the German "Verein für Kaschubische Volkskunde" (Society for Kashubian Folk Studies). While studying the folklore of the region, he did not forsake publishing in "Gazeta Gdańska".