Dora Sientje may be the same person as Dora Premsela, a pupil at the Middelbare Joodse Kunstnijverheidschool W.A. van Leer (the W.A. van Leer Jewish Secondary School of Applied Arts).
Source: Jan Teeuwisse, Leven en werk van beeldhouwer-tekenaar Jaap Kaas (Utrecht 1987), p. 89, noot 20
In addition, Jokos files (numbers 34642, 34644) on this family or other family members are at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.The Jokos files reveal that a claim was lodged for compensation for valuables surrendered to the Lippmann-Rosenthal looting bank (L-claim, number 9724/7801).