Following books and websites have been consulted for this experiment.
You are suggested to go through them for further details.

Bibliography

1. Fundamentals of Software Engineering, Rajib Mall, Prentice-Hall of India, 3rd Edition, 2009
2. THE UNIFIED MODELING LANGUAGE USER GUIDE, GRADY BOOCH, JAMES RUMBAUGH, IVAR JACOBSON, ADDISON-WESLEY, Low Priced Edition, 2000

Webliography

1. Class diagram
2. UML Tutorial: Part 1 -- Class Diagrams
3. Synchronous messages The UML
4. Asynchronous message , UML sequence diagram