And this - Su, B., Xiao, J., Underhill, P., Deka, R., Zhang, W., Akey, J., Huang, W., Shen, D., Lu, D., Luo, J., Chu, J., Tan, J., Shen, P., Davis, R., Cavalli-Sforza, L., Chakraborty, R., Xiong, M., Du, R., Oefner, P., Chen, Z., Lin, J. (1999) Y chromosome evidence for northward migration of modern humans in East Asia during the last ice age. Am.J.Hum.Genet., 65, 1718-1724.