Huston, Mary M. (1979). "Fee or Free: The Effect of Charging on Information Demand". Library Journal. 104 (16): 1811–1814. ERICEJ209864INISTPASCAL8030420646.
Huston, Mary M. (1979). "Fee or Free: The Effect of Charging on Information Demand". Library Journal. 104 (16): 1811–1814. ERICEJ209864INISTPASCAL8030420646.