Father: Josef Albert Frederiks
Registration Josef Albert Frederiks in 1913 in 's-Gravenhage (Netherlands) » Open Archives
https://archief.amsterdam/indexen/deeds/98533457-6998-56a3-e053-b784100ade19?person=98533457-6999-56a3-e053-b784100ade19
https://www.nationaalarchief.nl/onderzoeken/archief/2.19.323/invnr/1205/file/NL-HaNA_2.19.323_1205_0283