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:…sperm AR stimulated by progesterone, (Luconi et al., 1995; Meizel and Turner, 1996; Kirkman-Brown et al., 2002) and LPC- and A23187-induced AR are associated with higher levels of Tyr phosphorylation of p80 and p105 (Aitken et al., 1995; de Lamirande et al., 1998; de Lamirande and Gagnon, 2002).
Category: