Sohmer , H. and S. Freeman . "The Pathway for the Transmission of External Sounds into the Fetal Inner Ear" Journal of Basic and Clinical Physiology and Pharmacology, 12.2 (2011): 91-100. Retrieved 26 May. 2013, from doi:10.1515/JBCPP.2001.12.2.91

Sohmer , H. & Freeman , S. (2011). The Pathway for the Transmission of External Sounds into the Fetal Inner Ear. Journal of Basic and Clinical Physiology and Pharmacology, 12(2), pp. 91-186. Retrieved 26 May. 2013, from doi:10.1515/JBCPP.2001.12.2.91

Sohmer , H. and S. Freeman. 2011. The Pathway for the Transmission of External Sounds into the Fetal Inner Ear. Journal of Basic and Clinical Physiology and Pharmacology. 12(2): 91-186. Retrieved 26 May. 2013, from doi:10.1515/JBCPP.2001.12.2.91