Determinants of the essential one-carbon metabolism metabolites, homocysteine, S-adenosylmethionine, S-adenosylhomocysteine and folate, in cerebrospinal fluid - Smith, D E; Smulders, Y M; Blom, H J; Popp, J; Jessen, F; Semmler, A; Farkas, M; Linnebank, M (Clin Chem Lab Med, 2012)