"Based on ... the First International Symposium "Brothers and Sisters, Research on Sibling Relationships, Therapeutic Applications, held in Leyden, the Netherlands in December 1990. This symposium was organized by the Netherlands Organization for Postacademic Studies in the Social Sciences (PAOS), Academic Centre for Child and Adolescent Psychiatry (Curium) and the Dept. of Child and Adolescent Psychiatry at the University of Leyden"--P. ix.
