References
- Daw E., Walker J. Biological aspects of twin pregnancy in Dundee. Br J Obstet Gynaecol 1975; 82: 29–34
- Grennert L., Persson P., Gennser G., Gullberg B. Zygosity and intrauterine growth of twins. Obstet Gynecol 1980; 55: 684–87
- Scrimgeour J. B., Baker T. G. A possible case of superfetation in man. J Reprod Fertil 1974; 36: 69–73