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Purcell, S. M., Wray, N. R., Stone, J. L., Visscher, P. M., O'Donovan, M. C., Sullivan, P. F., Sklar, P., International Schizophrenia Consortium, and McGhee, K. A., 2009. Common polygenic variation contributes to risk of schizophrenia and bipolar disorder. Nature, 460 (7256), pp. 748-52.