Alternative, graph-theoretic attempts to solve this problem have been suggested and could implement the <hi xmlns="http://www.tei-c.org/ns/1.0" rend="italic">TEI abstract model</hi> through an adequate data structure (Huitfeldt 1994; Barnard et al. 1995; Sperberg-McQueen and Huitfeldt 2000; Huitfeldt and Sperberg-McQueen 2001; Durusau and O'Donnell 2002; Tennison and Piez 2002; Dipper 2005; Dekhtyar and Iacob 2005; Banski and Przepiórkowski 2009; Di Iorio, Peroni, and Vitali 2010; Di Iorio, Peroni, and Vitali 2011; Schmidt and Colomb 2009; Schmidt 2014; Götze and Dipper 2006; Peroni, Vitali, and Di Iorio 2009; Witt 2007; Kuczera 2016).