https://thejournalofheadacheandpain.biomedcentral.com/articles/10.1186/s10194-020-01199-y
https://thejournalofheadacheandpain.biomedcentral.com/articles/10.1186/s10194-020-01202-6
https://thejournalofheadacheandpain.biomedcentral.com/articles/10.1186/s10194-020-01197-0
https://thejournalofheadacheandpain.biomedcentral.com/articles/10.1186/s10194-020-01201-7
https://thejournalofheadacheandpain.biomedcentral.com/articles/10.1186/s10194-020-01198-z
https://thejournalofheadacheandpain.biomedcentral.com/articles/10.1186/s10194-020-01205-3
https://thejournalofheadacheandpain.biomedcentral.com/articles/10.1186/s10194-020-01200-8