human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "free articles and accounting for the timing effect"):
  Abstract: Various studies have attempted to assess the amount of free full text available on the web and recent work have suggested that we are close to the 50% mark for freely available articles (Archambault et al. 2013; Bjork et al. 2010; Jamali and Nabavi 2015). Our paper contributes to the literature by taking into account the timing issue by studying when the papers were made free

Includes members:
  Member "methods for estimating the size of google scholar":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "coverage of highly cited documents in google scholar web of science and scopus a multidisciplinary comparison")
  Member "does google scholar contain all highly cited documents 1950 2013":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "google scholar as a data source for research assessment")
  Member "green and gold open access percentages and growth by discipline":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "who pays comparing cost sharing models for a gold open access publication environment")

Question: Please tell me which class the source paper belongs to. The 40 classes are: cs.NA(Numerical Analysis), cs.MM(Multimedia), cs.LO(Logic in Computer Science), cs.CY(Computers and Society), cs.CR(Cryptography and Security), cs.DC(Distributed, Parallel, and Cluster Computing), cs.HC(Human-Computer Interaction), cs.CE(Computational Engineering, Finance, and Science), cs.NI(Networking and Internet Architecture), cs.CC(Computational Complexity), cs.AI(Artificial Intelligence), cs.MA(Multiagent Systems), cs.GL(General Literature), cs.NE(Neural and Evolutionary Computing), cs.SC(Symbolic Computation), cs.AR(Hardware Architecture), cs.CV(Computer Vision and Pattern Recognition), cs.GR(Graphics), cs.ET(Emerging Technologies), cs.SY(Systems and Control), cs.CG(Computational Geometry), cs.OH(Other Computer Science), cs.PL(Programming Languages), cs.SE(Software Engineering), cs.LG(Machine Learning), cs.SD(Sound), cs.SI(Social and Information Networks), cs.RO(Robotics), cs.IT(Information Theory), cs.PF(Performance), cs.CL(Computation and Language), cs.IR(Information Retrieval), cs.MS(Mathematical Software), cs.FL(Formal Languages and Automata Theory), cs.DS(Data Structures and Algorithms), cs.OS(Operating Systems), cs.GT(Computer Science and Game Theory), cs.DB(Databases), cs.DL(Digital Libraries), cs.DM(Discrete Mathematics). Directly output the class name.

gpt: cs.DL(Digital Libraries)