Rika Os and her husband are mentioned in the work of I. Cornelissen. In his book Ode aan een slecht mens. Oom Jopie uit de mediene (Amsterdam 1991) there also is a picture of her and her sisters on the pages 48 of 49.
The police commissioner of the State and Municipal police of Zwolle requested that Rika Passmann-Os, living at 17 Van Lennepstraat in Zwolle, be located, detained and brought to trial. She was suspected of having changed her place of residence without the required authorization. This description referred to Jews who had gone into hiding.
Algemeen Politieblad, nr 8, 25 February 1943, 211, notice 573
In addition, a Jokos file (number 10408) on this person is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.