I don't have any links, but I have read it about Vapor Station's juices more than once here on ECF over the past 18 months. Also, people who have talked to Eric (Vapor Station's owner/operator) have confirmed that he doesn't mix any of the VS juices. He designs the recipes with his flavorist in the Indian flavoring company, then the juices are manufactured, bottled, and labeled in India, and finally shipped to San Franciso as ready-to-sell pre-mix. It's a common practice, although India is unusual, as opposed to the U.S. or China.
So I guess I am not going to be about to get a 4x tart berry flavor any time soon. Thanks for the info.