Comonadicity and invertible bimodules

The purpose of this paper is to exhibit the main results of A. Masuoka [A. Masuoka, Corings and invertible bimodules, Tsukuba J. Math. 13 (1989) 353–362] and of L. El Kaoutit and J. Gómez-Torrecillas [L. El Kaoutit, J. Gómez-Torrecillas, Comatrix corings and invertible bimodules, Ann. Univ. Ferrara Ser. VII 51 (2005) 263–280] as special cases of a more general result.