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:Zif268 was chosen here since it is a transcription factor well characterized for its role in synaptic plasticity and memory processing (Bozon et al. 2003) and has been shown to be crucial in instrumental learning (Maroteaux et al. 2014).
Category: