POPOSPrivately-Owned Public Open Spaces (San Francisco, CA)
POPOSPost Office Point of Sale (advertising system; UK)
References in classic literature ?
But D'Artagnan knew too well all the folds and refolds of his Porthos, not to find a secret if there were one there; like those regular, minute old bachelors, who know how to find, with their eyes shut, each book on the shelves of their library and each piece of linen in their wardrobe.
He refolds it and lays it in his desk with a countenance as unperturbable as death.