1. Time, clocks, and the ordering of events in a distributed system;Lamport;ACM Commun. Comput. Algebra,1978
2. Events in computation;Winskel,1981
3. The Large Scale Structure of Space–Time;Hawking,1973
4. Techniques of Differential Topology in Relativity;Penrose,1972
5. The geometry of free fall and light propagation;Ehlers,1972