http://www.who.int World Health Organization adolescent stage http://www.who.int/maternal_child_adole ... ce/dev/en/ http://www.who.int/maternal_child_adole ... ce/dev/en/ World Health Organization - Adolescent Development http://www.who.int/maternal_child_adole ... ce/dev/en/ http://www.who.int/maternal_child_adole ... ce/dev/en/ Adolescent development http://www.who.int/maternal_child_adole ... ce/dev/en/