AGARWAL, Ravi P., O’REGAN, Donal and PRECUP, Radu. Fixed point theory and generalized Leray-Schauder alternatives for approximable maps in topological vector spaces. Topological Methods in Nonlinear Analysis. Online. 1 September 2003. Vol. 22, no. 1, pp. 193 - 202. [Accessed 22 July 2024].