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:As such, the residual stress can have profound inJuence on whether a putative fatigue crack grows
into a full-Jedged fatigue crack, determining its location, initiation and propagation when superimposed with cyclic loading and stress concentration (Boyce et al., 2001b; Peters et al., 2002).
Category: