Virtual Reality Design
The most up to date published version of POs is
Virtual Saltburn by the sea: Creative content design for virtual environments
Published by the Arts and Humamities Data Service 'Guides to Good Practice'.
The Perceptual Opportunities of an Ordinary Day
; an informal introduction to POs.
Understanding VR Brain
An out of date version of the PO model but
the 'Introduction' and 'Locating the Content of VEs' sections are relevant.