Scalar Logical time
- Lamport Clocks - University of Washington
- Time, Clocks and the Ordering of events in a Distributed System - Loyola University Chicago | Leslie Lamport
- Clocks and Synchronization
- Distributed Systems 3rd Edition | M. van Steen and A.S. Tanenbaum
- Distributed Computing: Principles, Algorithms, and Systems | A.D. Kshemkalyani and M. Singhal