sentences:  In 1952, based on the recommendations already put forward in the ICCs' report on "Invisible Barriers to Trade and Travel" from 1949, the contracting parties to GATT adopted an International Convention to Facilitate the Importation of Commercial Samples and Advertising Material proposed and drafted by the International Chamber of Commerce and which entered into force on 20 November 1955.During the meetings of the Seventh Session Working Party, which prepared the text of the Convention, and following a proposal by the French delegation, some consideration was given to the possibility of introducing a system of triptyques or carnets for samples of value carried by commercial travellers.It was suggested that such a system would alleviate the financial burdens and administrative formalities imposed upon firms sending representatives abroad.