id author title date pages extension mime words sentence flesch summary cache txt crl-12396 McGee, Rob Key Factors of Circulation System Analysis and Design 1972-03-01 13 .pdf application/pdf 5527 249 57 transactions be- tween the library and its users are cre- ated by combining user data, item data, and time data. Media (source records) and methods by which user data and item data may be initially presented to the system are indicated by Figures 3 and 4, which distinguish between the active participation of users in making their identifications, and the passive na- ture of items is being identified. cache/crl-12396.pdf txt/crl-12396.txt