"Nederland, Indexen van de Archieven, Primaire Archiefstukken (BS en DTB), 1600-2000," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:QLMV-BHHC : 22 August 2017), Nicolaas Kerkhoven in entry for Nicolaas Kerkhoven and Geertruida Maria Metselaar, Marriage 06 Oct 1927, Haarlem, Noord-Holland, Netherlands; from database, openarchives (https://www.openarch.nl : 2016); citing Haarlem, inventory number , record number 612; ; Noord-Hollands Archief.