I am also looking for Solbjørg Reiersen b. 28 Oct 1923 in Notodden. She is Erna's sister and their parents are Ruben Reiersen and Betzy J Olsen. Solbjørg married a man named Øymo first name and date unknown.
Betzy may have imigrated to Canada and then New Your, USA and then back to Norway. She appears to have had two children before marring Ruben.