Παραπομπή APA

Sasikumar Purameri. (2014). Stephen Hawking. Progress Publication.

Παραπομπή Chicago Style

Sasikumar Purameri. Stephen Hawking. Kozhikode: Progress Publication, 2014.

Παραπομπή MLA

Sasikumar Purameri. Stephen Hawking. Progress Publication, 2014.