Heart of Oak Readers?

[Alana in Canada]

I'm looking for the Heart of Oak Series of Readers by Charles Norton. I've found them on-line at Internet Archive (http://www.archive.org/search.php?query=subject%3A%22Nursery%20rhymes%22&page=2). It looks like a fabulous site.

But, I was wondering if there are any hard, physical copies out there?--well, other than $20 collector editions!
Thanks.