“…In this model there is no direct link among non-hub nodes and flow just distributed in the network through the hubs' linking. This is the case, for example in Abdinnour-Helm (1998), Chen (2007, Correia et al (2010b), Costa et al (2007), de Camargo and Miranda (2012, Ebery (2001), Krishnamoorthy (1996, 1999), Ilić et al (2010), Iwasa et al (2009), Kratica et al (2007, Labbé and Yaman (2004), Labbé et al (2005), Pirkul and Schilling (1998), Puerto et al (2011), Puerto et al (2013, Randall (2008), Silva andCunha (2009), Skorin-Kapov andSkorin-Kapov (1994), and Sohn and Park (2000). In the multiple allocation model, several nodes will be selected as a hub and other nodes, namely non-hub nodes (spoke), can connect to more than one hub.…”