1. The yoga-sūtras of Patañjali;Patañjali,1934
2. A source book in Indian philosophy;Radhakrishnan,1957
3. Essence of maharishi Patanjali’s Ashtang yoga;Mehta,2005
4. Philosophy of the unconscious; speculative results according to the inductive method of physical science;Hartmann,1931
5. The unconscious;Freud,1915