Before bending my brain around the succinct yet articulate definition of "whirling derivation," I thought I'd Google it. Just out of curiosity.

Whirling and stability of flywheel systems, part I: Derivation of combined and lumped parameter models

I came up with this from The Smithsonian/NASA Astrophysics Data System at this page.

Okay, so there's a little distance between them. But it is a great result!