Betje Gosschalk was a daughter of Jacob Gosschalk and Rachel Hartog van Geuns. She married Abraham Velleman in 1880 in Groningen. He died in 1915.
Addition of a visitor of the website
In addition, a Jokos file (number 9719) on this person is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.