A Summary of the International Standard Date and Time Notation
http://www.cl.cam.ac.uk/~mgk25/iso-time.html

Kuhn, Markus
Cambridge University
2000

Abstract:

International Standard ISO 8601 specifies numeric representations of date and time. This standard notation helps to avoid confusion in international communication caused by the many different national notations and increases the portability of computer user interfaces. In addition, these formats have several important advantages for computer usage compared to other traditional date and time notations. The time notation described here is already the de-facto standard in almost all countries and the date notation is becoming increasingly popular.