Reference values for serum lipids and lipoproteins in Spanish adolescents: the AVENA study - Ruiz, JR; Ortega, FB; Moreno, LA; Warnberg, J; Gonzalez-Gross, M; Cano, MD; Gutierrez, A; Castillo, MJ (Sozial- Und Praeventivmedizin, 2006)