Alan Thomas has posted Values, Reasons and Perspectives (Proceedings of the Aristotelian Society, 1996-7) on the web. Here is the abstract:
Two agents in a morally dilemmatic situation can agree on the values in that situation and their bearing on decision but come to different all things considered verdicts about what to do. It is argued that Sen’s notion of evaluator relativity in which outcomes differ in value according to whether one is the proposed author or viewer of the proposed action can be adapted to solve the problem. Practical reasons are perspectival in a more radical way than judgements of value, but still objective. Adapting Sen’s insight by explaining it as a claim about reasons not values solves the paradox while remaining cognitivist about values and impartialist about reasons.