Acock, Malcolm and Jackson, H. G. 1976. “Seems.”Revue Internationale de Philosophie 30: 304–330.
Jackson, Howard and Acock, Malcolm. 1976. “Sense and Sense-Data.” in Studien zu Frege III: Logik und Semantik, edited by Matthias Schirn, pp. 117–138. Problemata n. 44. Stuttgart - Bad Cannstatt: Friedrich Frommann Verlag - Günther Holzboog.