"Nederland, Indexen van de Archieven, Primaire Archiefstukken (BS en DTB), 1600-2000," database, FamilySearch (https://www.familysearch.org/ark:/61903/1:1:QLZH-F8R4 : 16 November 2020), Elisabeth Catharina Geertruida Proper in entry for Jacoba Hubertina Monne, Birth 11 May 1899, Utrecht, Nederland; from database, openarchives (https://www.openarch.nl : 2016); citing Utrecht, archive 481, inventory number 146-03, record number 1247; ; Het Utrechts Archief.