"Michigan, Marriages, 1822-1995," Database, FamilySearch (https://familysearch.org/ark:/61903/1:1:FCN1-GXS : accessed 19 June 2015), Hendrik Poort and Geertje Vankampen, 03 Jun 1881; citing reference Item 3 P 164 L 474; FHL microfilm 1,320,181.