Researchers Grow Sperm Stem Cells in Laboratory Cultures: Advance Could Lead to New Infertility Treatments, Source of Adult Stem Cells (11/03/2004, National Institute of Child Health and Human Development) - http://www.nih.gov/news/pr/nov2004/nichd-03.htm
Bone Marrow Transplantation and Peripheral Blood Stem Cell Transplantation: Questions and Answers (National Cancer Institute) - http://cis.nci.nih.gov/fact/7_41.htm