1. Intra-individual variation in commonly analyzed serum constituents;B, I.Morrison; A, Shenkin; A, McLelland;Clin Chem,1979
2. Factors contributing to intraindividual variation of serum constituents: 1. Within-day variation of serum constituents in healthy subjects;Statland, B.E.; Winkel, P.; Bokelund, H.;Clin Chem,1973
3. The effects of time of venepuncture on variation of serum constituents;Winkel, P.; Statland, B.E.; Bokelund, H.;Am J Clin Pathol,1975
4. Biological variability;Young, D.S.,1979
5. Circadian rhythms of blood minerals in humans;Markowitz, M.; Rotkin, L.; Rosen, J.F.;Science,1981