Deutsche Nationalbibliothek online catalog, viewed January 12, 2017 (authorized access point: Bartelink, Gerhardus J. M.; other data in authority record: variant forms of name: Bartelink, Gerhardus Johannes Marinus; Bartelink, G. J. M.; Dutch theologian; born 1924) http://d-nb.info/gnd/11892477X