Mattress Factory

https://www.pghcitypaper.com/pittsburgh/three-installation-artists-explore-the-spaces-we-inhabit/Content?oid=1931662

Installations of all sizes: Mattress Factory showcases 4 very different exhibits

http://triblive.com/aande/museums/9266013-74/factory-installations-mattress

Jornal de sciencias mathemáticas, physicas, e naturaes

https://books.google.com/books?id=fR4AAAAAMAAJ&pg=PA180&lpg=PA180&dq=spherodendron&source=bl&ots=Gn5nI4M-Gc&sig=cHdms-OWjZ_OTx_rdh404TMpfHw&hl=en&sa=X&ved=0ahUKEwjqstjQxJjVAhXF8z4KHV7hB7cQ6AEIwwEwHA#v=onepage&q=spherodendron&f=false