series of booklets series of books series of broadcasts series of buildings series of buttons series of calculations series of calls series of campaigns series of cards series of cartoons series of case studies series of cases series of caves series of challenges series of changes series of chapters series of characters series of checks series of choices series of circumstances series of civil wars series of clues series of codes series of coincidences series of coins series of columns series of commands series of comments series of commercials series of commitments series of communications series of competitions series of complaints series of compounds series of compromises series of computers series of concerts series of concrete actions series of concrete measures to a series of conditions series of conditions series of conferences series of conflicts series of considerations series of consultations series of contracts series of conversations series of corrections series of countries series of crimes series of crises series of criteria series of cultural events series of cuts series of dams series of data series of deaths series of debates series of decisions series of declarations series of defeats series of demands series of demonstrations series of difficulties series of directives series of disasters series of discussions series of documentaries series of documents series of dolls series of doors series of dots series of draft series of drawings series of earthquakes series of effects series of elements series of emails series of encounters series of equations series of errors series of essays series of events to a series of events series of examinations series of examples series of exciting series of exercises series of exhibitions series of experiences series of experiments series of explosions series of factors series of facts series of failures series of features series of files series of films series of filters series of fires series of flights series of fortifications series of functions series of furniture series of games series of guarantees series of guidelines series of guides series of hearings series of hills series of holes series of icons series of images series of important issues series of important measures series of improvements series of incidents series of indicators series of initiatives series of injections series of injuries series of innovations series of inspections series of instructions series of instruments series of interactions series of interviews series of investigations series of islands series of items series of jumps series of killings series of lakes series of lamps series of laws series of layers series of lectures series of lessons series of letters series of levels series of lies series of lights series of lines series of machines series of maps series of matches series of materials series of measurements to a series of measures series of measures series of mechanisms series of meetings series of mergers series of messages series of missions series of mistakes series of misunderstandings series of models series of modifications series of modules series of moments series of movements series of moves series of movies to a series of murders series of murders series of natural disasters series of negotiations series of new initiatives series of notes series of novels series of numbers series of objectives series of obligations series of observations series of obstacles series of operations series of opinions series of opportunities series of options series of other measures series of pages series of paintings series of pamphlets series of papers series of parameters series of peaks series of performances series of photographs series of photos series of pictures series of poems series of points series of policies series of portraits series of posters series of posts series of preparatory work series of presentations series of preventive measures