With regards to this post I thought here is something I can contribute unless already some one has. There is a very fascinating book which I am still trawling through of many, called "1421"!
It was published 2002 and written by "Gavin Menzies", a former submarine commander. He was born in China 1937 and since his seafaring knowledge which is extensive to say the least has retired, but has visited 120 countries and some 900 museums and libraries and far more besides in order of tracking down what the Chinese succeeded at well before Columbus etc.
He has his own sight for reference and review www.1421.tv
THE YEAR CHINA DISCOVERED THE WORLD. the result of fifteen years research and It became a best seller Kindest regards Brett.