1. Darryl G. Parry and Don C. Lawton, 1993, Analysis of direct wave arrivals in a shallow multi-offset reverse VSP, CREWES Research Report Volume 5
2. Saul E. Guevara*, Gary F. Margrave, Near-surface S-wave velocity from an uphole survey using explosive sources.
3. Near surface shear wave velocity versus depth profiles, NEHRP classifications for 27 sites in Puerto Rico.