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:Our results showed that the mean area of blastocysts that did implant and those that did not wasn‚Äôt statistically significant, in agreement with previous papers [28] suggesting that blastocysts of similar area have the same implantation potential.
Category: