Billen, J. and Al-Khalifa, M. S. (2015) “Morphology and ultrastructure of the pro- and postpharyngeal glands in workers of Pachycondyla sennaarensis”, Sociobiology. Feira de Santana, Brazil, 62(2), pp. 270–275. doi: 10.13102/sociobiology.v62i2.270-275.