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:Another mass transfer technique for film cooled endwalls was applied by Friedrichs et al. (1996) using the Ammonia-Diazo method for discrete hole film cooling. Jabbari et al. (1996) among others used the naphthalene sublimation technique for such an application. Using the latter method, the local mass transfer distribution can also be determined and related to the heat transfer by the analogy between mass and heat transfer (e.g. Han and Goldstein (2008)) and applied for discrete hole film cooling as well.
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