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N Engl J Med
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Article
in English
| MEDLINE
| ID: mdl-449986
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N Engl J Med
; 298(10): 566-7, 1978 03 09.
Article
in English
| MEDLINE
| ID: mdl-625313
3.
Am J Public Health Nations Health
; 58(3): 579-80, 1968 Mar.
Article
in English
| MEDLINE
| ID: mdl-18018217