title: Letter: Nocturnal cramps.
mesh_terms: D000368:Aged; D003035:Cobalt / Q000172:deficiency; D006801:Humans; D007267:Injections; D008875:Middle Aged; D009120:Muscle Cramp / Q000188:drug therapy*; D012075:Remission, Spontaneous; D013997:Time Factors; D014805:Vitamin B 12 / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D003035:Cobalt; D014805:Vitamin B 12