Seeking a reference to C Darwin's definitive work

[David L Dowe]

   I understand that Darwin postulates his theory of the "survival of the
fittest" in (please correct me if I'm wrong) 'The origin of (the) species'.

I would appreciate references to places where Darwin cites this theory,
including a complete reference to 'The origin of (the) species'.

My intention is to cite (some of) these in academic work.

Thank you.    - David D.

(Dr.) David Dowe, Dept of Computer Science, Monash University, Clayton,
Victoria 3168, Australia           dld at bruce.cs.monash.edu.au 
Fax:+61 3 905-5146