kˈeɪ. nˈoʊltən ænd ˈɛl. hˈɑːɹmən, "kəmpjˈuːɾɚpɹədˈuːst ɡɹˈeɪskeɪlz," kəmpjˈuːɾɚ ɡɹˈæfɪks ænd ˈɪmɪdʒ pɹˈɑːsɛsɪŋ nˈoʊ. wˈʌn, nˈaɪntiːnhˈʌndɹɪd sˈɛvənti tˈuː, pˌiːpˈiː.
K. Knowlton and L. Harmon, "Computer-Produced Greyscales," Computer Graphics and Image Processing No. 1, 1972, pp.