共 24 条
- [21] MATERNAL AGE, PARITY, SOCIAL-CLASS AND SEX-RATIO [J]. ANNALS OF HUMAN GENETICS, 1977, 41 (OCT) : 205 - 217
- [22] Say B, 1967, Turk J Pediatr, V9, P32
- [23] STRONG SJ, 1967, PLACENTA TWIN PREGNA, P38
- [24] WALSH R. J., 1955, AUSTRALIAN JOUR EXPTL BIOL AND MED SCI, V33, P189, DOI 10.1038/icb.1955.19