Astudiaeth 2002 o ymddygiad iechyd mewn plant oed ysgol : astudiaeth groes-genedlaethol Sefydliad Iechyd y Byd : astudiaeth ymchwil /
Wales.Health Promotion Division.
World Health Organization.
Caerdydd : Cynulliad Cenedlaethol Cymru,
2001.
Bound back to back and inverted.
Cover title.
Includes bibliographical references.
Health behavior in adolescence
Health behavior in children
School children