Abstract

Get full access to this article
View all access options for this article.
References
1.
Chalmers, I.
,
Enkin, M.
, &
Keirse, M.J.N.C.
(Eds.) (1989 ). Effective care in pregnancy and childbirth . Oxford, UK : Oxford University Press .
2.
Hunter, J. E.
, &
Schmidt, F. L.
(1990 ). Methods of meta-analysis: Correcting error and bias in research findings . Newbury Park, CA : Sage .
3.
Rosenthal, R.
(1991 ). Meta-analytic procedures for social research (Rev. ed. ). Newbury Park, CA : Sage .
