Popova, Gergana; Aarts, Bas; Denison, David and Keizer, Evelien. 2004. ‘The Nature of Grammatical Categories and Their Representation’. In: Gergana Popova; Bas Aarts; David Denison and Evelien Keizer, eds. Fuzzy Grammar: A Reader. Oxford: Oxford University Press, pp. 1-28. ISBN 978-0199262571 [Book Section]

Popova, Gergana; Aarts, Bas; Denison, David and Keizer, Evelien, eds. 2004. Fuzzy Grammar: A Reader. Oxford: Oxford University Press. ISBN 978-0199262571 [Edited Book]