This Technical Specification provides in Clause 7 the list of syntaxes that complies with and allows to express syntactically the core invoice model as specified in EN 16931 1:2017, according to the selection criteria provided by the Standardization Request [1]. The selection of the syntaxes also derived from the Standardization Request [1]. It states that, to limit costs on public authorities, the list should ideally not exceed five syntaxes. Four syntaxes were taken into account and assessed according to criteria provided by the Standardization Request [1].