"Journal of Perinatal Medicine - Official Journal of the WAPM", 20.6 (1992): 409-490. Retrieved 26 May. 2013, from http://www.degruyter.com/view/j/jpme.1992.20.issue-6/issue-files/jpme.1992.20.issue-6.xml

Journal of Perinatal Medicine - Official Journal of the WAPM (1992), 20(6), pp. 409-490. Retrieved 26 May. 2013, from http://www.degruyter.com/view/j/jpme.1992.20.issue-6/issue-files/jpme.1992.20.issue-6.xml

Journal of Perinatal Medicine - Official Journal of the WAPM. 1992. 20(6): 409-490. Retrieved 26 May. 2013, from http://www.degruyter.com/view/j/jpme.1992.20.issue-6/issue-files/jpme.1992.20.issue-6.xml