1. The Biology of Twinning in Man;Bulmer,1970
2. Associated Press, Correction: Twin-2 Dads Story, Associated Press, May 8, 2015. Available from: http://www.apnewsarchive.com/2015/Correction-Twins-2-Dads-story/id-2684b32fb9c7449491ecf3e8bff7e70e
3. How frequent is heteropaternal superfecundation?;Wenk;Acta Genet. Med. Gemellol.,1992
4. H. Assefa, New Jersey Judge Rules Twin Girls Have Different Fathers, May 8, 2015. Available from: http://www.cnn.com/2015/05/08/us/new-jersey-twins-two-fathers/index.html
5. A review of the mechanisms and evidence for typical and atypical twinning;McNamara;Am. J. Obstet. Gynecol.,2015