Garfield, Sidney R.; Collen, Morris F.; Feldman, Robert; Soghikian, Krikor; Richart, Robert H.; Duncan, James H. (1976-02-19). "Evaluation of an Ambulatory Medical-Care Delivery System". New England Journal of Medicine. 294 (8): 426–431. doi:10.1056/NEJM197602192940806. ISSN0028-4793. PMID813145.
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Garfield, Sidney R.; Collen, Morris F.; Feldman, Robert; Soghikian, Krikor; Richart, Robert H.; Duncan, James H. (1976-02-19). "Evaluation of an Ambulatory Medical-Care Delivery System". New England Journal of Medicine. 294 (8): 426–431. doi:10.1056/NEJM197602192940806. ISSN0028-4793. PMID813145.
Garfield, Sidney R.; Collen, Morris F.; Feldman, Robert; Soghikian, Krikor; Richart, Robert H.; Duncan, James H. (1976-02-19). "Evaluation of an Ambulatory Medical-Care Delivery System". New England Journal of Medicine. 294 (8): 426–431. doi:10.1056/NEJM197602192940806. ISSN0028-4793. PMID813145.