Ridout, J.B. & Carrasco, M. (1993). Olfactory perception and olfactory imagery: a multidimensional analysis. Jrl of Exptl Psych, 19(2): 287-301.

Abstract
Whether a system of imagery for olfaction exists is currently an unsettled issue. Moreover, the dimensions underlying odor perception have eluded researchers for many years. Two experiments bearing on these issues are presented. In one experiment, a group of 32 undergraduates rated the similarity of pairs of 16 commonplace odorants (e.g., chocolate and leather) they perceived using scratch and sniff stimuli; in another, a different group of 44 undergraduates was asked to imagine and then rate the similarity of the same pairs of odors. Multidimensional scaling of the data suggests that three-dimensional solutions with similar stimulus dimensions, such as fruitiness, strength, and familiarity, underlied the ratings of both perceived and imagined odors. By finding that similar dimensions define the psychological space of both the imagery and the perception tasks, this study suggests that imagery does indeed exist for olfaction.