Alfi OS, Chang R, Azen SP. Evidence for genetic control of non-disjunction in man. Am J Hum Genet 1980; 32:477 - 83.

Cereigo AI and Martinez -Frias ML. Consanguineous marriage among parents of patients with Down syndrome. Clin Genet 1993; 44: 221 - 2.

Hook EB, Cross PK, Mutton DE: Female predominance (low sex ratio) in 47,+21 mosaics. Am J Med Genet 1999;84:316 - 319.

Hay S, Barbano H. Independent effects of maternal age and birth order on the incidence of selected congenital malformations. Teratology 1972; 6:271 - 279.

Jyothy A, Kumar KS, Roa GN, Roa VB, Swarna M, Devi BU. Cytogenetic studies of 1001 Down syndrome cases from Andhra Pradesh, India. Indian J Med Res 2000; 111:133 - 7.

Stoll C, Alembik Y, Dott B, Roth MP. Epidemiology of Down syndrome in 118,265 consecutive births. Am J Med Genet Suppl 1990; 7:79 - 83.

Lejeune J, Gauthier M, Turpin R. Les chromosomes humanains en culture des tissues. CR Acad 1959; 248: 602 - 603.

Polani PE, Briggs JH, Ford CE. A mongol girl with 46 chromosomes. Lancet 1960; 1:721.

Clark CM, Edwards JH, Smallpiece V. 21 trisomy / normal mosaicism in an intelligent child with Mongoloid characteristics. Lancet 1961; 1:1028 - 1030.

Kovaleva NV, Butomo IV, Verlinskaia DK, II'iashenko TN, Pantova IG, Prozorova MV, Khitrikova le, Shandlorenko SK. Karyological characteristic of Down's syndrome: clinical and theoretical aspects. Tsitologiia 1999; 41:1014 - 21.

Palliam LH and Huether CA. Translocation Down syndrome in Ohio 1970 - 1981: epidemiologic and cytogenetic factors and mutation rate estimates. Am J Hum Genet 1986; 39: 361 - 70.

Grasso M, Giovamucci ML, Pierluigi M. Isochromosome not translocation in trisomy 21 q 21 q. Hum Genet 1989;84:63 - 65.

Shaffer LG, McCaskill C, Haller V. Further characterization of 19 cases of rear (21 q 21) and delineation as isochromosomes or robertsonian translocation in Down syndrome. Am J Med Genet 1993 47; 957 - 963.

Robinson WP, Bernasconi F, Basarans. A somatic origin of homologous robertsonian translocation and isochromosomes . Am J Hum Genet 1994; 54:290 - 302.