The Unified Process (UP) might not be generally considered to be an oohci method. However, UP as distributed by Rational Software Corporation features use case storyboards, one of many techniques to enhance use cases with usability data.

Use case storyboards are discussed in a chapter in Object Modeling and User Interface Design: Designing Interactive Systems and in Rational's UP product documentation. More general references on the Unified Process (which have almost nothing to do with user interface design) are:

view book info or buy:
Ivar Jacobson, Grady Booch & James Runbaugh "The Unified Software Development Process"

view book info or buy:
Philippe Kruchten "The Rational Unified Process, An Introduction"

Rational Unified Process at Rational's web site.