In the November 2012 edition of the renowned Backpacker Magazine, on page 12, you can find a full page article regarding the original trekking expedition: The Source of the Amazon, organized by Classic Travel in July 2012. The article was written by known journalist and travel enthusiast Eugene Buchanan, editor of Steamboat Today and member of the Explorers Club. Photo credits go to Michael Majcherczyk.
Backpacker Magazine has been around for almost 30 years and reaches the most active travelers in the U.S. In this article you can find a description of the trip to the source of the largest river in the world. Backpacker Magazine recommends Classic Travel, especially Yurek Majcherczyk, to contact when organizing such an adventure. The next trip to the Source of the Amazon is slated for August 3rd, 2013. More information here.
The original article can be found on Backpacker's official website