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

Bibliography

1. Object-Oriented Modeling and Design with UML, Michael Blaha, James Rumbaugh, Prentice-Hall of India, 2nd Edition
2. Object-Oriented Analysis and Design using UML, Mahesh P. Matha, Prentice-Hall of India,

Webliography

1. Use Case Diagrams
2. Use case diagram -- Wikipedia
3. Unified Modeling Language, Superstructure, V2.1.2
4. "Functional Requirements and Use Cases", Ruth Malan and Dana Bredemeyer, Bredemeyer Consulting
5. "A Use Case Template: draft for discussion", Derek Coleman, Hewlett-Packard Software Initiative
6. X. J. Zheng, X. Liu, & S. Liu. (2010). Use Case and Non-functional Scenario Template-Based Approach to Identify Aspects. Computer Engineering and Applications ICCEA 2010 Second International Conference on (Vol. 2, pp. 89-93)
7. Extend relationships
8. Requirements Trace-ability and Use Cases
9. UML Use Case Diagrams: Tips and FAQ