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:, 2002) and hydroxypropyl methylcellulose (HPMC) (Kushida and Gotoda, 2013; Miyazaki et al., 2011) or enteric polymers such as hydroxypropyl methylcellulose phthalate (HPMCP) (Miyazaki et al.
Category: