@article {pmid15010742, title = {Systematic review of statistical methods used to analyze Seattle Angina Questionnaire scores}, journal = {Can J Cardiol}, volume = {20}, number = {2}, year = {2004}, month = {Feb}, pages = {187{\textendash}193}, author = {Norris, C. M. and Ghali, W. A. and Saunders, L. D. and Brant, R. and Galbraith, P. D.} }