This paper is concerned with positive solutions of the boundary value problem (|y | p−2 y ) + f (y) = 0, y(−b) = 0 = y(b) where p > 1, b is a positive parameter. Assume that f is continuous on (0, +∞), changes sign from nonpositive to positive, and f (y)/y p−1 is nondecreasing in the interval of f > 0. The uniqueness results are proved using a time-mapping analysis. 2005 Elsevier Inc. All rights reserved.