human: Given a node-centered hypergraph: <hypergraph>, where nodes represent papers and hyperedges represent sets of papers co-cited by a source paper.

Details of the hypergraph:
Center node: "green and gold open access percentages and growth by discipline"
  Abstract: Most refereed journal articles today are published in subscription journals, accessible only to subscribing institutions, hence losing considerable research impact. Making articles freely accessible online ("Open Access," OA) maximizes their impact. Articles can be made OA in two ways: by self-archiving them on the web (“Green OA”) or by publishing them in OA journals (“Gold OA”). We compared the percent and growth rate of Green and Gold OA for 14 disciplines in two random samples of 1300 articles per discipline out of the 12,500 journals indexed by Thomson-Reuters-ISI using a robot that trawled the web for OA full-texts. We sampled in 2009 and 2011 for publication year ranges 1998-2006 and 2005-2010, respectively. Green OA (21.4%) exceeds Gold OA (2.4%) in proportion and growth rate in all but the biomedical disciplines, probably because it can be provided for all journals articles and does not require paying extra Gold OA publication fees. The spontaneous overall OA growth rate is still very slow (about 1% per year). If institutions make Green OA self-archiving mandatory, however, it triples percent Green OA as well as accelerating its growth rate.

Connected through hyperedge HE-1 (induced by source paper "who pays comparing cost sharing models for a gold open access publication environment"):
  with members:
    - "the state of open access in germany an analysis of the publication output of german universities"
    - "evidence of open access of scientific publications in google scholar a large scale analysis"
    - "constructing bibliometric networks a comparison between full and fractional counting"

Connected through hyperedge HE-2 (induced by source paper "do authors deposit on time tracking open access policy compliance"):
  with members:
    - "estimating open access mandate effectiveness the melibea score"

Connected through hyperedge HE-3 (induced by source paper "evidence of open access of scientific publications in google scholar a large scale analysis"):
  with members:
    - "developing indicators on open access by combining evidence from diverse data sources"
    - "can we use google scholar to identify highly cited documents"
    - "a two sided academic landscape portrait of highly cited documents in google scholar 1950 2013"
    - "the journal coverage of web of science and scopus a comparative analysis"
    - "methods for estimating the size of google scholar"

Connected through hyperedge HE-4 (induced by source paper "disentangling gold open access"):
  with members:
    - "self selected or mandated open access increases citation impact for higher quality research"
    - "positional effects on citation and readership in arxiv"
    - "does the arxiv lead to higher citations and reduced publisher downloads for mathematics articles"

Connected through hyperedge HE-5 (induced by source paper "free articles and accounting for the timing effect"):
  with members:
    - "methods for estimating the size of google scholar"
    - "does google scholar contain all highly cited documents 1950 2013"

Connected through hyperedge HE-6 (induced by source paper "green open access in computer science an exploratory study on author based self archiving awareness practice and inhibitors"):
  with members:
    - "a framework for systematic analysis of open access journals and its application in software engineering and information systems"
    - "does the arxiv lead to higher citations and reduced publisher downloads for mathematics articles"
    - "ten year cross disciplinary comparison of the growth of open access and how it increases research citation impact"
    - "the effect of use and access on citations"

Connected through hyperedge HE-7 (induced by source paper "estimating open access mandate effectiveness the melibea score"):
  with members:
    - "self selected or mandated open access increases citation impact for higher quality research"

Connected through hyperedge HE-8 (induced by source paper "testing the finch hypothesis on green oa mandate ineffectiveness"):
  with members:
    - "self selected or mandated open access increases citation impact for higher quality research"

Question: Please tell me which class the center node 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)