DIGO: An Open Data Architecture for e-Government. - Alexandre Lopes Machado; José Maria Parente de Oliveira (EDOCW, 2011)

Modelo conceitual formal de relacionamentos do ordenamento jurídico positivo. - Alexandre Lopes Machado (2013)

A Legal Ontology of Relationships for Civil Law System. - Alexandre Lopes Machado; José Maria Parente de Oliveira (ONTO.COM/ODISE@FOIS, 2014)