Frank Drake equation to estimate the number of worlds in our galaxy that might harbor intelligent life. Also know as the Sagan Equation.
Houseboat Propeller Regulation Proposed and Withdrawn by USCG: Analysis by PGIC
History of Boat Propeller Safety
Mitigating Boat Propeller Injuries & Fatalities Chart
Approaches to Prevent Outboard Motors From Flipping Into Boats After Striking Floating or Submerged Objects
Why Outboards Used in Bass Tournaments Disproportionately Break Off & Flip into Boats Compared to Other Outboard Motors
Four Volume Review of the Boating Industry’s Boat Propeller Guard Product Liability Defense