This thesis consists of three chapters on international trade. The first chapter examines the trading relationship of American and Colombian firms in the context of the U.S.-Colombia Free Trade Agreement. It distinguishes between spot sourcing and relational sourcing strategies depending on the trading patterns of the firms. Firms relying on relational sourcing are characterised as paying higher prices, placing smaller orders, and having longer lasting trading relationships than their peers (similar to a just-in-time management system). The main findings of the paper are that these are the firms that export the most under the FTA, and, surprisingly, their exports increase the more restrictive the rule of origin (RoOs) of the traded goods are. This phenomenon occurs because the defining characteristics of relational sourcing happen to be ideal conditions for the firms to make the investments necessary to comply with the rules and benefit from the preferential tari rates of the agreement. The second chapter is a purely theoretical work, and it examines the interdependence of global value chains (GVCs) and rules of origin. Employing a heterogeneous firms trade model, it finds that the optimal number of stages for production for a GVC increases the cheaper the foreign intermediate inputs are, and decreases the more restrictive the RoOs. Additionally, it shows that firms that operate as GVCs have much larger incentives to comply with the RoO than the rest of the exporting firms. The third chapter takes a much broader perspective. It presents a new extensive database on rules of origin by the OECD and the World Bank which is not yet publicly available. Using this data, a novel indicator to measure the restrictiveness of the rules of origin is constructed, and incorporated into an augmented trade gravity model. The main findings of the study suggest a negative relationship between restrictive rules of origin and bilateral trade. However this negative effects are mitigated by certain facilitating provisions of the agreement such as allowing different kinds of cumulation schemes with third countries.