Recently I wrote a research paper on the said topic, and here are the links I published:
- Original, updated version @ GitHub – https://github.com/ninethsense/VirtualQueue/blob/master/README.md
- Medium – https://medium.com/@ninethsense_8477/yet-another-virtual-queue-management-system-design-44cdee123a0b
Additionally, a small excerpt in a Malayalam online news paper – https://www.janmabhumi.in/read/bevq-failure-is-a-lesson-how-to-build-the-best-virtual-queue-app/