@article{eprints1422,
            year = {2012},
          author = {Guido Caldarelli and Matthieu Cristelli and Andrea Gabrielli and Luciano Pietronero and Antonio Scala and Andrea Tacchella},
         journal = {PloS One},
           title = {A Network Analysis of Countries? Export Flows: Firm Grounds for the Building Blocks of the Economy},
          number = {10},
          volume = {7},
           month = {October},
           pages = {e47278},
       publisher = {Public Library of Science},
        abstract = {In this paper we analyze the bipartite network of countries and products from UN data on country production. We define the country-country and product-product projected networks and introduce a novel method of filtering information based on elements? similarity. As a result we find that country clustering reveals unexpected socio-geographic links among the most competing countries. On the same footings the products clustering can be efficiently used for a bottom-up classification of produced goods. Furthermore we mathematically reformulate the ?reflections method? introduced by Hidalgo and Hausmann as a fixpoint problem; such formulation highlights some conceptual weaknesses of the approach. To overcome such an issue, we introduce an alternative methodology (based on biased Markov chains) that allows to rank countries in a conceptually consistent way. Our analysis uncovers a strong non-linear interaction between the diversification of a country and the ubiquity of its products, thus suggesting the possible need of moving towards more efficient and direct non-linear fixpoint algorithms to rank countries and products in the global market.{\ensuremath{<}}/p{\ensuremath{>}}},
             url = {http://eprints.imtlucca.it/1422/}
}