Maybe not a "sighting", but a significant reference.

Wikipedia article on Apollo 13.

Mentioned the University of Toronto calculations for the improvised "air pressure" separation of the Lunar Module from the Command Module.

Section 3.3, "Crew Survival"; final paragraph.

"The last problem to be solved was how to separate the Lunar Module asafe distance away from the Command Module just before re-entry. Thenormal procedure was to use the Service Module's reaction control system (RCS) to pull the CSM away after releasing the LM along with theCommand Module's docking ring, but this RCS was inoperative because ofthe power failure, and the useless SM would be released before the LM.To solve the problem, Grumman called on the engineering expertise of the University of Toronto. A team of six UT engineers, led by seniorscientist Bernard Etkin, was formed to solve the problem within a day. The team concluded thatpressurizing the tunnel connecting the Lunar Module to the CommandModule just before separation would provide the force necessary to pushthe two modules a safe distance away from each other just prior tore-entry. The team had 6 hours to compute the pressure required, using slide rules.. They needed an accurate calculation, as too high a pressure mightdamage the hatch and its seal, causing the astronauts to burn up; toolow a pressure would not provide enough separation distance of the LM.Grumman relayed their calculation to NASA, and from there in turn to the astronauts, who used it successfully.^[26]"