Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:…the invasive pathogen, Listeria monocytogenes, induces the mono-ubiquitination of receptors – hepatocyte growth factor receptor (HGFR) (Veiga and Cossart, 2005) and E-cadherin and triggers the recruitment of clathrin and caveolin-1 to entry foci (Bonazzi and Cossart, 2006; Veiga et al., 2007).
Category: