(:notitlegroup:) 

   @article{jasa88b,
    title     = {Estimation of Surface Noise Source Level from Seismo-Acoustic Ambient Noise
                Measurements},
    author    = {Henrik Schmidt and William A. Kuperman},
    journal   = {Journal Acoustical Society of America},
    pages     = {2153--2162},
    volume    = {84},
    year      = {1988}}