Many of the disparities were attributable to
vast differences in the amount and
value of taxable property within school systems, which ranged from a few hundred dollars to millions of dollars
in taxable revenue per pupil.
As such, I don't think the ProCD case applies
in my situation due to the qualitative
differences between licensing CD - ROMs with
vast amounts of information that has been compiled and which has
value added search features added to it versus the «sale» of single copies of public domain sheet music (however, a library that creates and licenses for sale a CD - ROM with hundreds of individual pieces of public domain sheet music might be protected by the principles
in ProCD since a court might recognize and protect the library's investment of time and money
in creating the CD - ROM, but even
in that situation, if the library is not otherwise adding
value - added information above and beyond the public domain content, it is not obvious that ProCD applies).