References
- Clarke , C. A. and Sheppard , P. M. 1956 . The ABO blood groups in duodenal ulcer. . Acta Gen. Stat. Med. , 6 : 570 – 574 .
- Fuller , John B. and Thompson , W. Robert . 1960 . Behavior Genetics. , New York : John Wiley and Sons .
- Holmes , S. J. 1924 . The size of college families. . J. Hered. , 15 : 407 – 415 .
- McConnell , R. S. 1956 . Selection and the ABO blood locus. . Ann. N. Y. Acad. Sci. , 65 : 12 – 25 .
- This investigation was supported by a research grant, B‐2356, from the National Institute of Neuro1ogical Diseases and Blindness, Public Health Service.