Ju Qiu, Zhongbo Zhang and Wenfeng Pan. (2013). Fast Acoustic Imaging for a 3D Penetrable Object Immersed in a Shallow Water Waveguide.
            <i>Journal of Computational Mathematics</i>. <i>31</i> (5).
            449-469.
         doi:10.4208/jcm.1304-m3983