J. Grispolakis and E. D. Tymchatyn, "Continua which are images of weakly confluent mappings only", Houston Journal of Mathematics, vol. 6, no. 3, pp. 483-502, 1980.
Continua which are in Class (W) (i.e. images ofweakly confluent mappings only) were introduced by A. Lelek.Many classes of continua have been shown to be in Class (W).Recently the authors characterized Class (W) in terms of acovering property of hyperpspaces as well as in terms of anembedding property. They had also given some geometricconditions which imply Class (W). In this paper an attempt ismade to show that certain geometric properties are alsonecessary for being in Class (W). It is shown that planar continuain Class (W) are atriodic, and that being in Class (W) is not aWhitney property. Finally, there are given some characterizationsfor these continua which are images of pseudo confluentmappings only.