Arun Kumar Uppal, “Comparative Effect of Two duration Load Methods and Interval Running Method on Cardio Respiratory Endurance and Selected Physiological Variables”, (Unpublished Doctorial Dissertation, Jiwaji University, Gwalior 1980).
Bosen, Training without straining (The Scholars Foundation, Delhi 1972) pp 181
CR Kothari, “Research Methodology, Methods and Techniques”, Jan.1999, p.51.
Duane Knudson (1999), “Issues in Abdominal Fitness: Testing and Technique: The Journal of Physical Education, Recreation and Dance, Vol.70, 1999.