Correction to “On some subspaces of Banach spaces whose duals are 𝐿₁ spaces”

E. Casini, E. Miglierina, L. Piasecki, and L. Veselý have recently constructed an example of an L 1 L_{1} -predual hyperplane W W of c c which does not contain a subspace isometric to c c , in spite of the fact that the closed unit ball of W W contains an extreme point. This example shows that Remark A of Section 4 of [Proc. Amer. Math. Soc. 23 (1969), pp. 378-385], titled as above, is false. The purpose of this note is to present two correct versions of that Remark A and a short proof of our 1969 main result.