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: "trends in russian research output indexed in scopus and web of science"
  Abstract: Trends are analysed in the annual number of documents published by Russian institutions and indexed in Scopus and Web of Science, giving special attention to the time period starting in the year 2013 in which the Project 5-100 was launched by the Russian Government. Numbers are broken down by document type, publication language, type of source, research discipline, country and source. It is concluded that Russian publication counts strongly depend upon the database used, and upon changes in database coverage, and that one should be cautious when using indicators derived from WoS, and especially from Scopus, as tools in the measurement of research performance and international orientation of the Russian science system.

Connected through hyperedge HE-1 (induced by source paper "a tale of two databases the use of web of science and scopus in academic papers"):
  with members:
    - "funding information in web of science an updated overview"
    - "google scholar web of science and scopus a systematic comparison of citations in 252 subject categories"
    - "missing author address information in web of science an explorative study"
    - "book reviews in academic journals patterns and dynamics"
    - "publish or impoverish an investigation of the monetary reward system of science in china 1999 2016"
    - "the journal coverage of web of science and scopus a comparative analysis"
    - "large scale analysis of the accuracy of the journal classification systems of web of science and scopus"
    - "global maps of science based on the new web of science categories"

Connected through hyperedge HE-2 (induced by source paper "prevalence of potentially predatory publishing in scopus on the country level"):
  with members:
    - "the journal coverage of web of science and scopus a comparative analysis"
    - "a new methodology for comparing google scholar and scopus"
    - "a review of the literature on citation impact indicators"
    - "a further step forward in measuring journals scientific prestige the sjr2 indicator"
    - "some modifications to the snip journal impact indicator"

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)