1. Muscle cramps in athletes;Manjra,1991
2. Cramping study in 2600 endurance athletes;Kantarowski;Med Sci Sports Exerc,1990
3. Systematic reviws;Chalmers,1995
4. NHS. Centre for Reviews and Diseminations. Undertaking systematic reviews of research effectiveness. University of York; 1996.
5. Cramps;Layzer;N Eng J Med,1991