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:This pattern of crypt hyperplastic enteropathy also characterizes many infective states [21, 22], but in our Zambian population villous height and crypt depth are positively correlated [18], as occurs during starvation [23].
Category: