Hi, Article reproduction can improve keyword position ? how many article sites and how many articles could be done for improve the keyword position ?
submit as many as articles as possible but never submit a same article in 2-3 article submission sites i.e. an article is good to submit only in 2-3 sites.
No one can give you exact numbers...Numbers never plays big role in SEO but Quality matters.. So start syndicating your articles in quality websites or blogs targeting your keywords, and you will see an improvement in keyword position..
Reproduction means rewriting the same article again and again? I don't think this is a good idea. Try to use new keywords in all articles and provide different contents. It might help.