TY  - RPRT
TI  - Cluster headache and its variants.
AU  - O Sjaastad
PY  - 1988
DO  - 10.1111/j.1526-4610.1988.hed2810667.x
UR  - https://pubmed.ncbi.nlm.nih.gov/3229999/
ID  - 3229999
ER  -