Hill, A., Nicholls, R., Thein, S., & Higgs, D. (1985). Recombination within the human embryonic xi-globin locus: A common xi-xi chromosome produced by gene conversion of the psi xi gene.

Hill, A., R. Nicholls, S. Thein, and D. Higgs. Recombination Within the Human Embryonic Xi-globin Locus: A Common Xi-xi Chromosome Produced by Gene Conversion of the Psi Xi Gene. 1985.

Hill, A., et al. Recombination Within the Human Embryonic Xi-globin Locus: A Common Xi-xi Chromosome Produced by Gene Conversion of the Psi Xi Gene. 1985.