[merloen]

This paper is a classic: Time, Clocks, and the Ordering of Events in a Distributed System: http://www.ics.uci.edu/~cs230/reading/time.pdf

[wicknicks]

The above link is a summary to the paper. Here is the actual publication: http://cnlab.kaist.ac.kr/~ikjun/data/Course_work/CS642-Distr...