Re: when & how discriminatory pricing for serials began, see:

Wittig, Glenn R. (1977). Dual pricing of periodicals. College & Research
Libraries 38(5):412-418.

  Wittig states that the practice of charging libraries a different rate
began "as early as the mid-1950s" (p.415). He reports that 4% of
journals had a dual price structure in 1966, rising to 15% in 1975. "The
mean incremental difference in 1975 among these journals was almost $7
per title. The institutional subscription rates are rising at a
significantly faster pace than are rates for individuals and,
consequently, can have a very marked impact on periodical budgets" (p.
415).

  Wittig discusses xerography in libraries as an important reason for
dual pricing. Publishers believed that photocopying in libraries reduced
sales to individuals (p. 417), and thus justified dual rates.

Steve Black
Reference, Serials, and Instruction Librarian
The College of Saint Rose
392 Western Avenue
Albany, NY 12203-1419
blacks@strose.edu
(518)458-5494