Stefan Hallgren, Håkan Olsén. 2010. Effects on Guppy brain aromatase activity following short-term steroid and 4-Nonyl phenol exposures. Environmental Toxicology 25: 261-271 (in press).

Stefan Hallgren, Maria Linderoth, Håkan Olsén. 2006. Inhibition of cytochrome p450 brain aromatase reduces two male specific sexual behaviours in the male Endler guppy (Poecilia reticulata). General and Comparative Endocrinology 147: 323-328.

Other academic

Stefan Hallgren. 2009. Brain Aromatase in the guppy, Poecilia reticulata - Distribution, control and role in behaviour. Doctoral thesis. Department of Zoology, Stockholm University.

Stefan Hallgren. 2006. Neuroestrogen and male reproductive behaviour in the guppy. Licentiate thesis..

Stefan Hallgren, Satish-Srinivas Kitambi. Cloning, sequencing and In situ localisation of guppy brain aromatase, cyp19b.

Stefan Hallgren, Håkan Olsén. Impacts of synthetic oestrogen and antioestrogen treatments on courtship and mating behaviours in male guppies (Poecilia reticulata).