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:One of these closely mimics the localizations we have observed of phorbol ester binding associated with protein kinase C (Worley et al., 1986a) and of the G, protein, which may be linked to the phosphinositide cycle (Worley et al., 1986~).
Category: