@article {poppeliers2013first,
    AUTHOR = {Poppeliers, Christian and Puno{\v{s}}evac, Predrag and Bell, Tammy},
     TITLE = {Three-Dimensional Seismic-Wave Gradiometry for Scalar
              Waves},
   JOURNAL = {Bulletin of the Seismological Society of America},
  FJOURNAL = {Bulletin of the Seismological Society of America},
    VOLUME = {103},
      YEAR = {2013},
    NUMBER = {4},
     PAGES = {2151--2160},
      ISSN = {0037-1106},
       DOI = {10.1785/0120120224}
       URL = {http://www.bassaonline.org/content/103/4},
}