Abstract
This project was inspired by the extensive contribution of Nordic researchers to the English language twin literature. the purpose of the study was to compile a source bibliography of twin literature written at Nordic institutions. the bibliography compiled as a supplement for this paper provides as complete a survey as is possible to obtain in the United States. Our search began with a Medline Computer data base. to make our survey more complete, we cross-referenced and added to this using the Index Medicus, the National Institute of Mental Health Bibliography, Excerpta Medica, specific article references, references provided by Nordic university libraries and Gedda's Estudio dei Gemelli. the full bibliography of 313 references is available at no cost from the Center for the study of multiple Birth, Rm. 476, 333 E. Superior, Chicago, III. 60611, U.S.A.