[78] Article 8 of the Convention (bilateral and multilateral cooperation) provides that «the Parties may continue existing bilateral or multilateral agreements or other arrangements with a view to fulfilling their obligations under this Convention, or enter into new bilateral or multilateral agreements or other arrangements. Such agreements or other arrangements may be based on the elements listed in Annex VI (elements of bilateral and multilateral cooperation). Trade in services is growing faster than trade in goods (Koncz and Flatness, 2007). As a result, multilateral and bilateral trade negotiations have increasingly taken into account services issues. While negotiations can be difficult in general, it has been particularly difficult for services. It could come from the quality of the services. First, there are different types of services that could be an obstacle to the early conclusion of an agreement. The four modes of transport are: cross-border trade in services (mode 1), consumption abroad (mode 2), commercial presence (mode 3), temporary movement of natural persons (type 4). . . .