On the website of Joods Monument is recorded that Betje Sips-Tokkie has died in Birkenau on 20 October 1942. The data of her death comes from her certificate of death A1139, drawn up on 23 May 1946 in Den Haag by order of the First Chamber of the District Court of Den Haag, showing that she would have been died in Auschwitz-Birkenau in Poland on 20 October 1942.
Later archival research has shown however that the data as stated in her death certificate cannot be correct and are incorrect; the archives of the Red Cross and the registration card of Betje Sips-Tokkie of the file cabinet of the Jewish Council, show, that she was put on transport with the entire family from Westerbork to Auschwitz on 26 October 1942.
Transports from Westerbork to Auschwitz usually took three days. And because the Joseph Sips family was deported as a whole on 26 October, and mothers with little children on arrival usually were sent to the gas chambers immediately, it is more than most likely that Betje Sips-Tokkie, as mother of the 3-year old Leon Sips, not on 20 October, but together with Leon Sips, i.e. on 29 October 1942 has been killed in the gas chamber of Auschwitz-Birkenau.
The real date and place of death for Betje Sips-Tokkie would therefore be: Auschwitz-Birkenau, 29 October 1942.
On the website Joods Monument always the official Dutch date of death is maintained as stated after the war by the Dutch Ministry of Justice or established by order of the District Court and recorded in a certificate of death.
Sources include the archive of the Dutch Red Cross, transports from Westerbork; the file cabinet of the Jewish Council, registration cards of Joseph Sips, Betje Sips-Tokkie and Leon Sips; the Wikipedia website jodentransporten vanuit Nederland.nl.