This program is developed in the group of Sjors Scheres at the MRC Laboratory of Molecular Biology, with contributions from the following people (in alphabetical order):

- Tom Burnley (from the CCP-EM team at STFC)
- Alister Burt (from David Barford's group at the MRC-LMB)
- Liyi Dong
- Bjoern Forsberg (from the Lindahl group at SciLifeLabs)
- Shaoda He
- Matt Iadanza (from the CCP-EM team at STFC)
- Dari Kimanius
- Erik Lindahl
- Takanori Nakane
- Joaquin Oton (from the Briggs group at MRC-LMB)
- Colin Palmer (from the CCP-EM team at STFC)
- Euan Pyle (from Giulia Zanetti's group at Birkbeck)
- Sjors Scheres
- Jasenko Zivanov

RELION also contain pieces of code from the following packages:

- XMIPP by COS Sorzano et al: http:/xmipp.cnb.csic.es
- BSOFT by JB Heymann et al: http://lsbr.niams.nih.gov/bsoft/
- HEALPIX by NASA Jet Propulsion Laboratory: http://healpix.jpl.nasa.gov/
- libLBFGS by N Okazaki: http://www.chokkan.org/software/liblbfgs/
- Numerical diagonalization of 3x3 matrices by J Kopp: https://www.mpi-hd.mpg.de/personalhomes/globes/3x3/index.html
- Gravis by Graphics and Vision Research Group at University of Basel: https://gravis.dmi.unibas.ch/index.html
- CPlot2D by AM Zsaki: http://www.amzsaki.com/?page_id=2073
- cmake-modules by RA Pavlik: https://github.com/rpavlik/cmake-modules
- Symmetry relaxation patch by V Abrishami 

Original disclaimers in the code of these external packages have been maintained as much as possible.
Please contact Sjors Scheres (scheres@mrc-lmb.cam.ac.uk) if you feel this has not been done correctly.

We also thank those who reported bugs and suggested fixes. They are acknowledged in the Git commit messages.