The Higher Education in the Academy in the UK has [a page devoted to Peer Observation](http://www.heacademy.ac.uk/resources.asp?process=filter_fields§ion=generic&type=some&id=12) that includes several background reports and research documents.
Gosling’s widely-cited [set of guidelines](http://www.escalate.ac.uk/resources/peerobservation2/) is published on a HE Academy related site.
A [case study](http://www.business.heacademy.ac.uk/resources/reflect/conf/2003/shortland/) by Sue Shortland.