The opening hours of public libraries

Do the opening hours of public libraries give some help to their main aim ? In this paper, the study of evolution of opening hours of head public libraries, between 1980 and 1991, is followed by the consideration of the real notion of opening hours. What kind of choices are made by the heads of the libraries (opening on sunday, opening at night, single opening and closing schedules, etc.), for what kind of libraries and for what kind of supply ?