"Electronic charts". International Maritime Organization (IMO). Archived from the original on 15 April 2013. Retrieved 5 June 2013.
army.mil
chl.erdc.usace.army.mil
"Heave Compensation For Hydrographic Surveying"(PDF). Coastal Engineering Technical Note. Vicksburg, Mississippi: U.S. Army Engineer Waterways Experiment Station, Coastal Engineering Research Center. March 1985. Archived from the original(PDF) on 14 June 2007.
"Heave Compensation For Hydrographic Surveying"(PDF). Coastal Engineering Technical Note. Vicksburg, Mississippi: U.S. Army Engineer Waterways Experiment Station, Coastal Engineering Research Center. March 1985. Archived from the original(PDF) on 14 June 2007.