The references below, added by the creator of this map, do not seem to contain specific info om the distribution of L-M20; see talk:
Sadaf Firasat, Shagufta Khaliq, Aisha Mohyuddin, Myrto Papaioannou, Chris Tyler-Smith, Peter A Underhill and Qasim Ayub, "Y-chromosomal evidence for a limited Greek contribution to the Pathan population of Pakistan," European Journal of Human Genetics (2007) 15, 121–126.
R. Spencer Wells et al., "The Eurasian Heartland: A continental perspective on Y-chromosome diversity," Proceedings of the National Academy of Sciences of the United States of America (August 28, 2001)
Yunusbaev 2006.
Michael F. Hammer, Tatiana M. Karafet, Hwayong Park, Keiichi Omoto, Shinji Harihara, Mark Stoneking and Satoshi Horai, "Dual origins of the Japanese: common ground for hunter-gatherer and farmer Y chromosomes," Journal of Human Genetics Volume 51, Number 1 / January, 2006.
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