Christopher M. O'Connor George S. Cree Ken McRae Conceptual Hierarchies in a Flat Attractor Network: Dynamics of Learning and Computations. 665-708 2009 33 Cognitive Science 4 http://dx.doi.org/10.1111/j.1551-6709.2009.01024.x db/journals/cogsci/cogsci33.html#OConnorCM09