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 "factors influencing cities publishing efficiency"):
  Abstract: Recently, a vast number of scientific publications have been produced in cities in emerging countries. It has long been observed that the publication output of Beijing has exceeded that of any other city in the world, including such leading centres of science as Boston, New York, London, Paris, and Tokyo. Researchers have suggested that, instead of focusing on cities' total publication output, the quality of the output in terms of the number of highly cited papers should be examined. However, in the period from 2014 to 2016, Beijing produced as many highly cited papers as Boston, London, or New York. In this paper, I propose another method to measure cities' publishing performance; I focus on cities' publishing efficiency (i.e., the ratio of highly cited articles to all articles produced in that city). First, I rank 554 cities based on their publishing efficiency, then I reveal some general factors influencing cities' publishing efficiency. The general factors examined in this paper are as follows: the linguistic environment, cities' economic development level, the location of excellent organisations, cities' international collaboration patterns, and the productivity of scientific disciplines.

Includes members:
  Member "the relationship among research productivity research collaboration and their determinants":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "china may need to support more small teams in scientific research")
  Member "the sum of it all revealing collaboration patterns by combining authorship and acknowledgements":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "funding information in web of science an updated overview")
  Member "a spatial scientometric analysis of the publication output of cities worldwide":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "on the challenges ahead of spatial scientometrics focusing on the city level")
  Member "the journal coverage of web of science and scopus a comparative analysis":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "a tale of two databases the use of web of science and scopus in academic papers")
  Member "evaluating university research same performance indicator different rankings":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "field normalization of scientometric indicators")
  Member "the european union china and the united states in the top 1 and top 10 layers of most frequently cited publications competition and collaborations":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "on the challenges ahead of spatial scientometrics focusing on the city level")
  Member "international scientific collaboration of china collaborating countries institutions and individuals":
    also connected through other hyperedges:
      - Hyperedge HE-7 (induced by source paper "academic collaboration rates and citation associations vary substantially between countries and fields")
  Member "mapping excellence in the geography of science an approach based on scopus data":
    also connected through other hyperedges:
      - Hyperedge HE-8 (induced by source paper "on the challenges ahead of spatial scientometrics focusing on the city level")

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)