diff --git a/doc/source/about.rst b/doc/source/about.rst
index a4e19dc..025d360 100644
--- a/doc/source/about.rst
+++ b/doc/source/about.rst
@@ -38,14 +38,20 @@ Acknowledging or citing ctools
 ------------------------------
 
 If you use ctools for work/research presented in a publication we ask you
-that you include the following standard acknowledgment:
+to include the formal reference
+
+   J. Knödlseder, M. Mayer, C. Deil, J.-B. Cayrou, E. Owen, N. Kelley-Hoskins,
+   C.-C. Lu, R. Buehler, F. Forest, T. Louge, H. Siejkowski, K. Kosack,
+   L. Gerard, A. Schulz, P. Martin, D. Sanchez, S. Ohm, T. Hassan, and
+   S. Brau-Nogué, 2016, A&A, in press (`arXiv:1606.00393 <http://arxiv.org/abs/1606.00393>`_)
+
+in your paper and that you add the following acknowledgment:
 
    *This research made use of ctools, a community-developed analysis package
    for Imaging Air Cherenkov Telescope data. ctools is based on GammaLib,
    a community-developed toolbox for the high-level analysis of astronomical
    gamma-ray data.*
 
-
 If you wish, you can also include a link to http://cta.irap.omp.eu/ctools/
 (if the journal allows this) in addition to the above text.