Erna came to the Netherlands on November 27th, 1939 according to the woningkaart of the house on the Niuwe Kerkstraat. Ruth and Rosa came to the Netherlands earlier: on January 7th, 1939. Their mother, Lea Grunberg, born on 14.04.1904 in Chenziny came to Amsterdam on 21.04.1939. Rosa and Ruth stayed in Soesterberg and in the Burgerweeshuis in Amsterdam before moving in with their mother in October 1939 (Rosa) and January 1940 (Ruth).
Their father was Hermann, born on 31.12.1899 in Chenziny. He had been taken to Poland in 1938 and is believed to have died there.
Source: National Archive, 2.04.58, inv 130 and others.
Addition