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:We additionally analyzed blood levels of the hematopoietic cytokine granulocyte colony-stimulating factor (G-CSF) since it might be the mediator of increased CD34 /KDR and CD45 /CD34 cell mobilization (11, 26).
Category: