General Agreement on Tariffs and Trade 1947(adopted 30 October 1947, entered into force 1 January 1948) 55 UNTS 187.
General Agreement on Tariffs and Trade 1994 (adopted 15 April 1994, entered into force 1 January 1995) 1867 UNTS 190.
For texts of subsequent agreements interpreting various articles see WTO Legal Texts link below
Meetings of member states to negotiate further developments in multilateral trade
The General Agreement on Tariffs and Trade: a commentary by 
Trade in Goods: the GATT and the other WTO agreements regulating trade in goods by Established in Geneva in 1995 (after the Uruguay Round negotiations (1986-94)), the World Trade Organization succeeded GATT (the organization) and now is the body which
• Administers GATT/WTO trade agreements
• Is a Forum for trade negotiations
• Handles trade disputes
• Monitors national trade policies
• Supplies Technical assistance and training for developing countries
Subject search to try in SOLO
World Trade Organization -- Rules and practice
Note: You may find that our near neighbour, the Bodleian Social Science Library, has works in this area too.!
The Oxford Handbook on the World Trade Organization by 
The Development of World Trade Organization Law : examining change in international law by