I just looked
at the new Scientific American (ah, the advantages of
working in a library) and skimmed the article. I may have missed it
but I don't see any instances of the author citing Wikipedia as a
source. The article does include a link to Wikipedia under a list of
"More to Explore" weblinks, which seems an entirely proper use.
This all depends on how rigidly you look at the term "source".
Scientific American does not typically have a lot of footnotes, but it
does give opportunities such as this for further exploration. Are you
saying that this makes the magazine less credible?