SPSS, Inc., Chicago, Ill., & SPSS, I. (1990). SPSS categories. SPSS.
Chicago Style (17th ed.) CitationSPSS, Inc., Chicago, Ill., and Inc SPSS. SPSS Categories. Chicago, Ill. [u.a.]: SPSS, 1990.
MLA (8th ed.) CitationSPSS, Inc., Chicago, Ill., and Inc SPSS. SPSS Categories. SPSS, 1990.
Warning: These citations may not always be 100% accurate.