He is married to Joukje Hoekstra.
They got married on December 23, 1905 at Achtkarspelen (Fr) , he was 26 years old.Source 3
They were married in church on February 12, 1920 at Utrecht (Ut) , he was 40 years old.The couple were divorced from February 12, 1920 at Utrecht (Ut) .Source 4
Geboorteregister 1879, Opsterland
https://www.graftombe.nl/names/info/419611/werkman
Huwelijksregister 1905, Achtkarspelen, Aktenummer 95
Huwelijksregister 1920, Achtkarspelen, Aktenummer 91