Kallen B., Castilla E.E., Lancaster P.A., Mutchinick O., Knudsen L.B., Martinez-Frias M.L., Mastroiacovo P., Robert E. The cyclops and the mermaid: an epidemiological study of two types of rare malformation : journal. — Journal of Medical Genetics, 1992. — Т. 29. — б. 30—5. — doi:10.1136/jmg.29.1.30 — PMID 1552541.
Kallen B., Castilla E.E., Lancaster P.A., Mutchinick O., Knudsen L.B., Martinez-Frias M.L., Mastroiacovo P., Robert E. The cyclops and the mermaid: an epidemiological study of two types of rare malformation : journal. — Journal of Medical Genetics, 1992. — Т. 29. — б. 30—5. — doi:10.1136/jmg.29.1.30 — PMID 1552541.