  A Deza graph G with parameters (n,k,b,a) is a k-regular graph with n vertices
such that any two distinct vertices have b or a common neighbours, where b >=
a. The children G_A and G_B of a Deza graph G are defined on the vertex set of
G such that every two distinct vertices are adjacent in G_A or G_B if and only
if they have a or b common neighbours, respectively. In this paper we present a
general approach to dual Seidel switching and investigate Deza graphs whose
children are strongly regular graphs.
