Yeah I had to figure that stuff out for myselfBy the time you set out to do this, the science and mathematics of heating was well up and running. Experts worked in labs and in building basements as stationary engineers.
The articles you read were written by less involved people. A descriptive article in a trade mag or Popular Mechanics would have bits of intel but "filler pieces" have always littered the road to research.
Knowledge is still not "given away" or magically imparted.