Rebecca Blok was the daughter of Jozef Blok and Clara Cohn. She was not married and had a son, Alexander Jozef Blok.
Amsterdam Municipal Archives; record card of Rebecca Blok
According to a list with shops of Jewish owners, compiled by the Amsterdam police in 1940, this family had a coffee house, address: Weesperzijde 46 in Amsterdam.
Abstracts of the police archives which are currently at the Amsterdam municipal archives