The relative importance of friendship to happiness increases with age

• Inmyung Song,

  Roles Conceptualization, Formal analysis, Investigation, Writing – original draft, Writing – review & editing

  Affiliation Department of Health Administration, Kongju National University, Gongju, South Korea

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• Jin-Won Kwon,

  Roles Conceptualization, Investigation

  Affiliation BK21 Four Community-Based Intelligent Novel Drug Discovery Education Unit, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu, South Korea

  https://orcid.org/0000-0003-3467-7805

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• Soo Min Jeon

  Roles Formal analysis, Writing – original draft, Writing – review & editing

  * E-mail: soomin0108@naver.com

  Affiliation Jeju Research Institute of Pharmaceutical Sciences, College of Pharmacy, Jeju National University, Jeju, South Korea

  https://orcid.org/0000-0002-5100-5739

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