Therearethreebasickindsofmaterialsthatcan"befoundinanygoodlibrary.First,therearebooksonallsubjects,bothinEnglishandinmanyotherlanguages.Thesebooksareorganizedaccordingtosubject,title,andauthorinacentralfilecanedthecardcatalog.Bookscangenerallybecheckedoutofthelibraryandtakenhomeforaperiodoftwotofourweeks.Second,therearereferenceworks.whichincludeencyclopedias,dictionaries,bibliography,atlases,etc.,andwhichgenerallymustbeusedinthelibraryitself.Third,thereareperiodicals-magazines,newspapers,pamphlets-whicharefliedalphabeticallyinracks,orwhichhavebeenfilmedtoconservespace.Likereferenceworks,periodicalscannotusuallyberemovedfromthelibrary.