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:‚Ä¶leaf litter were transferred into scintillation vials and stored in a solution of ethanol/formalin (70 %/10 % volume,
 which minimized mass loss; Leuven et al. 1985; von Schiller and Solimini 2005) until later identification (generally genus or species level; Tachet et al. 2000; Vieira-Lanero‚Ä¶
Category: