- Şafak Alpay, Ali Binhadjah, Eduard Yu. Emel'yanov, “A Positive Doubly Power Bounded Operator
with a Nonpositive Inverse Exists on any Infinite-dimensional AL-Space”, Positivity, 10, no. 1, 2006, 105

- Jochen Glück, Ulrich Groh, “A note on the positivity of inverse operators acting on C⋆-algebras”, Linear Algebra and its Applications, 708, 2025, 337
