Marv all of these online calculators and engineering books are super handy. Many would be even better if they were downloadable and printable
One can always do a print screen of a particular page of interest when needed for the times when going online or a view screen is just not practical I guess. But as a hedge against modern technology I'm still trying to rebuild my hard copy library when ever possible. The problem here is I can never replace my foot notes and dog eared text books, or scribbling on the cuffs of my shirts so to speak, like Ole Doc Methuselah from over 50 years of collecting.