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:…Additionally, similar to the nomenclature of rice gene ID in RGAP (http://rice.plantbiology.msu.edu/index.shtml),
maize gene ID in PLAZA is given according to the chromosomal location, which is convenient for the following research (http://bioinformatics.psb.ugent.be/plaza/) (Proost et al. 2015).
Category: