Operational Transform
- http://operational-transformation.github.io/
- https://jzhao.xyz/thoughts/Operational-Transform
- http://objcer.com/2018/03/05/SharePen-Operational-Transformation/
- https://fitzgeraldnick.com/2011/04/05/operational-transformation-operations.html
- https://github.com/ottypes/text
- https://digitalfreepen.com/2018/01/04/operational-transform-hard.html
- Operational Transformation Frequently Asked Questions and Answers
- https://hackernoon.com/operational-transformation-the-real-time-collaborative-editing-algorithm-bf8756683f66
- https://svn.apache.org/repos/asf/incubator/wave/whitepapers/operational-transform/operational-transform.html