Douwe van der Meer and Vroukje Sinnema were double cousins. They were first cousins with common ancestors Douwe Sijtzes van der Meer and Trijntje Klazes. They were second cousins with common ancestors Tjebbe Eelses Sinnema and Pietje Jans.
Huwelijksakte Tietjerksteradeel, 1819,akte nr. 26