- Published in March 2019
- 220 pages
- 20 original research papers, 1 corrigendum
- Published in July 2019
- 198 pages
- 20 original research papers
- Published in September 2019
- 222 pages
- 17 original research papers, 1 survey
This volume of the International Journal “Notes on Number Theory and Discrete Mathematics” is published with the financial support of the Bulgarian National Science Fund, Grant Ref. No. KP-06-NP-28/2018.