Publications of the United Nations Commission on International Trade Law have recently ben made available in the United Nations Law Collection in Hein Online. UNCITRAL is the core legal body of the UN's system for international trade law.
The publications available consist of both legislative texts (e.g. conventions, model laws) and non-legislative texts (e.g. UNCITRAL Arbitration Rules / UNCITRAL Conciliation Rules).
To access, go to Hein Online and scroll down the Subscribed Libraries list to 'United Nations Law Collection'. Enter this collection and under 'Publications' you'll see a link through to this newly added material.