He is married to Anna Catharina Maria Boonstra.
They got married on October 23, 1940 at Kollumerland c.a., Friesland, Nederland, he was 28 years old.Source 3
Klaas Johannes Douma | ||||||||||||||||||
1940 | ||||||||||||||||||
Anna Catharina Maria Boonstra |
Geboorteregister 1912, Kollumerland c.a.
https://www.graftombe.nl/names/info/82311/douma
Huwelijksregister 1940, Kollumerland c.a.