TY  - JOUR
A1  - Joseph, K.S. 
A1  - Kramer, M.S.
A1  - Marcoux, S.
A1  - Ohlsson, A.
A1  - Wu Wen, S. 
A1  - Allen, A.
A1  - Platt, R.
T1  - Determinants of preterm birth rates in Canada from 1981 through 1983 and from 1992 through 1994
Y1  - 1998
DO  - 10.1056/NEJM199811123392004
JF  - The New England Journal of Medicine
VL  - 339
IS  - 20
SP  - 1434
EP  - -1439

ER  -