Neil B. Shulman, Richard M. Levinson, G. E. Alan Dever, Richard S. Porter, Sandra L. Owen, W. Dallas Hall,
Impact of Cost Problems on Morbidity in a Hypertensive Population American Journal of Preventive Medicine. ,vol. 7, pp. 374- 378 ,(1991) ,
10.1016/S0749-3797(18)30874-2