Thanks to M. Hanke and Y. Halchenko for data and packaging.
There is no paper published yet about nilearn. We are waiting for the package to mature a bit. However, the patterns underlying the package have been described in: Machine learning for neuroimaging with scikit-learn.
We suggest that you read and cite the paper. Thank you.
A huge amount of work goes in the scikit-learn. Researchers that invest their time in developing and maintaining the package deserve recognition with citations. In addition, the Parietal team needs the citations to the paper in order to justify paying a software engineer on the project. To guarantee the future of the toolkit, if you use it, please cite it.
See the scikit-learn documentation on how to cite.