Text ( visual ) : unmediated Formal logic / A.N. Prior. -- Oxford : Clarendon Press , 1955. -- ix, 329 p. : ill. ; 23 cm. -- Includes bibliographical references. -- (BA27602868) ; https://ci.nii.ac.jp/ncid/BA27602868 Author Heading(s): Prior, Arthur N.. -- Classification(s): DC18 : 135.3