Added Brett et al 2001 reference.

Author: danlurie

docs/citing.rst

@@ -242,3 +242,7 @@ Other relevant references
   .. [Power2017] Power JD, Plitt M, Kundu P, Bandettini PA, Martin A (2017) Temporal interpolation alters
       motion in fMRI scans: Magnitudes and consequences for artifact detection. PLOS ONE 12(9): e0182939.
       doi:`10.1371/journal.pone.0182939 <https://doi.org/10.1371/journal.pone.0182939>`_.
+      
+  .. [Brett2001] Brett M, Leff AP, Rorden C, Ashburner J (2001) Spatial Normalization of Brain Images with 
+      Focal Lesions Using Cost Function Masking. NeuroImage 14(2) 
+      doi:`10.006/nimg.2001.0845 <https://doi.org/10.1006/nimg.2001.0845>`_.