A novel method is presented for identifying the source of weathered petroleum by measuring the similarity between the spectrum of a weathered oil and spectra of artificially weathered samples. The Pearson correlation coefficient is used as the similarity measure, and three separate <i>K</i>-nearest neighbor approaches are tested on the data set.
Carl D. Baer and Chris W. Brown, "Identifying the Source of Weathered Petroleum: Matching Infrared Spectra with Correlation Coefficients," Appl. Spectrosc. 31, 524-527 (1977)