Team, S. “On the Fine Spectra of the Generalized Forward Difference Operator ∆v Over the Sequence Space ℓ1: Javad Fathi, Rahmatollah Lashkaripour”. Thai Journal of Mathematics, vol. 9, no. 3, Dec. 2011, pp. 605-17, https://thaijmath2.in.cmu.ac.th/index.php/thaijmath/article/view/290.