I admit I just had a quick look at the article, but I think it only concerns general litterature.
If you consider technical books (medical/law reference titles, dictionaries or encyclopedias), one can spend more than 50 US$.
Few examples:
Encyclopedia Brittanica, the Harriet Lane Handbook, Canale, Mosby, Griffith's, PDR, ...
In this specific case, eBooks have more functionalities than paperback (instant lookup, calculators, cross references between articles, ...).
|