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: "international scientific collaboration of china collaborating countries institutions and individuals"
  Abstract: Using bibliometric methods, we investigate China’s international scientific collaboration from three levels of collaborating countries, institutions and individuals. We design a database in SQL Server, and make analysis of Chinese SCI papers based on the corresponding author field. We find that China’s international scientific collaboration is focused on a handful of countries. Nearly 95 % international co-authored papers are collaborated with only 20 countries, among which the USA account for more than 40 % of all. Results also show that Chinese lineage in the international co-authorship is obvious, which means Chinese immigrant scientists are playing an important role in China’s international scientific collaboration, especially in English-speaking countries.

Connected through hyperedge HE-1 (induced by source paper "academic collaboration rates and citation associations vary substantially between countries and fields"):
  with members:
    - "dimensions a competitor to scopus and the web of science"
    - "google scholar web of science and scopus a systematic comparison of citations in 252 subject categories"
    - "international research collaboration novelty conventionality and atypicality in knowledge recombination"
    - "the relationship among research productivity research collaboration and their determinants"
    - "three practical field normalised alternative indicator formulae for research evaluation"
    - "is collaboration among scientists related to the citation impact of papers because their quality increases with collaboration an analysis based on data from f1000prime and normalized citation scores"
    - "national disciplinary and temporal variations in the extent to which articles with more authors have more impact evidence from a geometric field normalised citation indicator"
    - "the journal coverage of web of science and scopus a comparative analysis"

Connected through hyperedge HE-2 (induced by source paper "research leadership flow determinants and the role of proximity in research collaborations networks"):
  with members:
    - "the sum of it all revealing collaboration patterns by combining authorship and acknowledgements"

Connected through hyperedge HE-3 (induced by source paper "factors influencing cities publishing efficiency"):
  with members:
    - "the relationship among research productivity research collaboration and their determinants"
    - "the sum of it all revealing collaboration patterns by combining authorship and acknowledgements"
    - "a spatial scientometric analysis of the publication output of cities worldwide"
    - "the journal coverage of web of science and scopus a comparative analysis"
    - "evaluating university research same performance indicator different rankings"
    - "the european union china and the united states in the top 1 and top 10 layers of most frequently cited publications competition and collaborations"
    - "mapping excellence in the geography of science an approach based on scopus data"
    - "the detection of hot regions in the geography of science a visualization approach by using density maps"

Connected through hyperedge HE-4 (induced by source paper "does the web of science accurately represent chinese scientific performance"):
  with members:
    - "publish or impoverish an investigation of the monetary reward system of science in china 1999 2016"
    - "the normalization of co authorship networks in the bibliometric evaluation the government stimulation programs of china and korea"
    - "a comparison between the china scientific and technical papers and citations database and the science citation index in terms of journal hierarchies and inter journal citation relations"

Connected through hyperedge HE-5 (induced by source paper "the dynamically changing publication universe as a reference point in national impact evaluation a counterfactual case study on the chinese publication growth"):
  with members:
    - "on the calculation of percentile based bibliometric indicators"
    - "towards a new crown indicator some theoretical considerations"

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)