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:Meristems were fixed and embedded in Steedman‚Äôs wax according to a previously described protocol (Paciorek et al., 2006) and sectioned at 8 mm by a microtome (Leica CM3050S).
Category: