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:They are applicable in scenarios such as designing questions for reading comprehension (Du et al., 2017; Zhou et al., 2017a; Yuan et al., 2017), and justifying the visual understanding by generating questions to a given image (video) (Mostafazadeh et al.
Category: