D. J.  Martins and Johnson, S. D., ?Distance and quality of natural habitat influence hawkmoth pollination of cultivated papaya?, International Journal of Tropical Insect Science, vol. 29, no. 3, pp. 114-123, 2009.

D. J.  Martins and Johnson, S. D., ?Hawkmoth pollination of aerangoid orchids in Kenya, with special reference to nectar sugar concentration gradients in the floral spurs?, American Journal of Botany, vol. 94, no. 4, pp. 650-659, 2007.

M. G.  Balducci, Martins, D. J., and Johnson, S. D., ?Pollination of the long-spurred African terrestrial orchid Bonatea steudneri by long-tongued hawkmoths, notably Xanthopan morganii?, Plant Systematics and Evolution, vol. 305, pp. 765-775, 2019.

S. D.  Johnson, Balducci, M. G., Bijl, A., Castañeda-Zárate, M., Cozien, R. J., Ortmann, C. R., and van der Niet, T., ?From dusk till dawn: camera traps reveal the diel patterns of flower feeding by hawkmoths?, Ecological Entomology, vol. XX, no. X, pp. [1-5], 2019.

C.  Micheneau, Johnson, S. D., and Fay, M. F., ?Orchid pollination: from Darwin to the present day?, Botanical Journal of the Linnean Society of London, vol. 161, pp. 1-19, 2009.