XYY Syndrome
(Wikipedia)
XYY Syndrome (NORD)
XYY syndrome (Genetics Home Reference)
Information Sheet: XYY Syndrome (Society for the Study of Behavioral Phenotypes (UK)) Karyotype image of XYY Syndrome (University of Washington)
The Fetus with XYY and His Parents
Sex Chromosome Problems Discovered Through Prenatal Diagnosis: 47,XYY Syndrome (Pacific Northwest Regional Genetics Group) Birth Defects Risk Factor Series: 47,XYY (Revised 2005) (Texas Department of Health Services)