No audio in the linked article, but some of the recordings referenced can be found here:

https://folkways.si.edu/magazine-fall-winter-2012-listening-...

Search on "Spotify" for "Tony Schwartz". They have 5 of his albums up there.

Camptown Races

Tony Schwartz records the Sounds of Children

You're Stepping on my Shadow

The World in My Mailbox

Music in the Streets

As I understand it, the idea was to put the whole collection online. I would love that, but I cannot find the pertaining link. Did I get it wrong?