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:For all in vivo measurements of protein synthesis with SUnSET (Goodman et al., 2011b), puromycin solution was prepared by diluting the appropriate volume of the stock solution that was needed to inject micewith 0.04 µmol/g body weight in 200 µl of PBS, and subsequently administered into the animals…
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