References
- Byrns , R. and Healy , J. 1936 . The intelligence of twins . J. Genet. Psychol. , 49 : 474 – 478 .
- Davis , E. A. 1937 . The development of linguistic skill in twins, singletons, siblings and only children from age five to ten years , Minneapolis : Univ. Minnesota Press .
- Day , E. J. 1932 . The development of language in twins . Child Devel , 3 : 298 – 316 . 179–99
- Newman , H. H. , Freeman , F. N. and Holzinger , K. J. 1935 . Twins , Chicago : Univ. Chicago Press .
- Meier , N. C. 1939 . Factors in artistic aptitude: Final summary of a ten-year study of a special ability . Psychol. Monog. , 51 ( No. 5 ) : 140 – 158 .
- Smith , M. E. 1926 . An investigation of the development of the sentence and the extent of vocabulary in young children . Univ. Ia. Stud., Stud. Child Welfare , 3 ( No. 5 )
- Smith , M. E. 1949 . Measurement of vocabularies of young bilingual children in both of the languages used . J. Genet. Psychol. , 74 : 305 – 310 .
- Smith , M. E. 1935 . A study of some factors influencing the development of the sentence in preschool children . J. Genet. Psychol. , 46 : 182 – 212 .
- Thorndike , E. L. 1939 . Your City. New York, Harcourt, Brace