ɪn nˈaɪntiːnhˈʌndɹɪd sˈɪksti ˈeɪt, dˈoːɹ bˈoʊθwɛl ænd mˈɑːɹliz mˈeɪfiːld ɹˈoʊt nˈoʊtən ɔnðɪ ˌɪntɚɹˈækʃən ʌv pˈɑːzᵻtˌɪv ænd nˈɛɡətˌɪv spˈeɪsᵻz.
In 1968, Dorr Bothwell and Marlys Mayfield wrote Notan – on the Interaction of Positive and Negative Spaces.