If you are researching Zrenjanin and Banat and if you read Serbian there are 2 interesting sources on Jewish Digital Library. I don't know Serbian but it was possible to copy parts of the text (PDF file) and translate them using Google translate.
To download the works click on the button "full text" under the pictures.
1. Jevreji u kulturi i prosveti Zrenjanina. (Jews in the culture and education of Zrenjanin)
2. Učešće Jevreja u razvoju privrede Banata: prilozi za monografiju o Jevrejima u Banatu (Contribution of the Jews to Banats economic progress)