"Journal of Perinatal Medicine - Official Journal of the WAPM", 17.2 (1989): 77-168. Retrieved 25 May. 2013, from http://www.degruyter.com/view/j/jpme.1989.17.issue-2/issue-files/jpme.1989.17.issue-2.xml

Journal of Perinatal Medicine - Official Journal of the WAPM (1989), 17(2), pp. 77-168. Retrieved 25 May. 2013, from http://www.degruyter.com/view/j/jpme.1989.17.issue-2/issue-files/jpme.1989.17.issue-2.xml

Journal of Perinatal Medicine - Official Journal of the WAPM. 1989. 17(2): 77-168. Retrieved 25 May. 2013, from http://www.degruyter.com/view/j/jpme.1989.17.issue-2/issue-files/jpme.1989.17.issue-2.xml