Raw, A. 1976. Behavior of males of solitary bee osmia-rufa (megachilidae) searching for females. Behaviour. 56, pp. 279-285. https://doi.org/10.1163/156853976x00055
Free, J. B. and Williams, I. H. 1972. The role of the Nasonov gland pheromone in crop communication by honeybees (Apis mellifera L.). Behaviour. 41 (3/4), pp. 314-318.
Free, J. B. 1971. Stimuli Eliciting Mating Behaviour of Bumblebee (Bomb Us Pratoruml.) Males. Behaviour. 40 (1/2), pp. 55-61. https://doi.org/10.1163/156853971X00320
Free, J. B. 1970. Effect of flower shapes and nectar guides on the behaviour of foraging honeybees. Behaviour. 37 (3/4), pp. 269-285. https://doi.org/10.1163/156853970X00376
Free, J. B. and Williams, I. H. 1970. Exposure of the Nasonov gland by honeybees (Apis mellifera) collecting water. Behaviour. 37 (3/4), pp. 286-290. https://doi.org/10.1163/156853970X00385
Free, J. B. and Butler, C. G. 1955. An analysis of the factors involved in the formation of a cluster of honeybees. Behaviour. 7 (1), pp. 304-316. https://doi.org/10.1163/156853955X00111