I just purchased "science and engineering mathematics with the hp 49g" volumes 1 and 2 by Dr. Gilberto E. Urroz. In general I think they are great, but in my copy of volume 2, every occurrence of the single quote character in the code samples, and apparently a few other symbols, are replaced by a small square symbol. It seems like it may have been printed with an incorrect or missing font. Are all copies of volume 2 that way?

In scanning through my copy of Urroz's second volume, I saw many examples of code with single quotation marks, and did not see any with the difficulty that you describe. If you gave a particular example of the difficulty you see, with page number, I could give a more positive response.