Headache Disorders, Primary

• Anqing Municipal Hospital — Anqing, Anhui, China
• The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital) — Wuhu, Anhui, China
• Beijing Tiantan Hospital, Capital Medical University — Beijing, Beijing Municipality, China
• Beijing Chaoyang Hospital — Beijing, Beijing Municipality, China

• Children's Mercy — Kansas City, Missouri, United States

• Ribeirão Preto Medical School - University of São Paulo (FMRP-USP) — Ribeirão Preto, São Paulo, Brazil

• Texas Tech University Health Sciences Center — Lubbock, Texas, United States

• Kaiming Liu — Hangzhou, Zhejiang, China

• Kaiming Liu — Hangzhou, Zhejiang, China

• International University of Cataluña — Barcelona, Spain

Not specified

• Rigshospitalet Glostrup — Glostrup Municipality, Denmark

• AnkaraCHBilkent — Ankara, Turkey (Türkiye)