He is married to Maria Helena Gerdes.
They got married on June 18, 1935 at Emmen, Gemeente Emmen, Drenthe, Nederland, he was 22 years old.Source 4
Child(ren):
grandparents
parents
brothers/sisters
children
Johan Gerard - Geert Hartmann | ||||||||||||||||||||||||||||||||||||
1935 | ||||||||||||||||||||||||||||||||||||
Maria Helena Gerdes | ||||||||||||||||||||||||||||||||||||

Pauline Berens: Genealogienetwerk zus Greetje Berens voorheen EemslandBoekweitBoerenImmigratie
https://www.genealogieonline.nl/the-dutch-connection/I21086.php
Johan Gerard Hartmann bidprentje