DESCRIPTION:
References:

http://nmr.cit.nih.gov/xplor-nih/xplorMan/node339.html - Mainly goes into how NCS can be used in X-PLOR, a structure determination program, but gives good example of how it can be applied

http://www.ccp4.ac.uk/html/refmac5/usage/tls_usage.html#reference3 - goes into a good amount of detail on what TLS is, what it is useful for and the benefit of using this method. It then goes on to describe how to use it in REFMAC, a program designed for the refinement of macromolecule structures.

Brunger, A., Nilges, M., 1993. Computational challenges for macromolecular structure determination by X-ray crystallography and solution NMR-spectroscopy. Quarterly reviews of biophysics 26(1) pp 49-125 - A very in depth look at the challenges of determining structure, goes into a lot of detail, maybe more than is needed for this course. But it does have a very good section on density modification.

http://my.yetnet.ch/dergutemensch/crystallography/refinement.htm - Very good for brief information on what refinement is, what the R factor and free R factors are, before going on to talk about the different methods, giving a very short description of each one. One of the best for a quick general overview of refinement.

Jones, T., A., and Kleywegt, G., J., 1997. Good Model-building and Refinement Practice [Online]. Uppsala university, Uppsala. Available from: http://xray.bmc.uu.se/gerard/gmrp/gmrp.html [Accessed 16/11/15] - The source goes into excellent detail about problems that arise during refinement and why as well as emphasising the need for model rebuilding and refinement to go hand in hand.

Afonine, P., n.d. Crystallographic Structure Refinement [Online]. Lawrence Berkeley National Laboratory: Berkeley. Available from: https://www.phenix-online.org/presentations/latest/pavel_refinement_general.pdf [Accessed 16/11/15] - Provides excellent detail on problems arising from low resolution data and how they can be resolved or combatted. It contains many useful diagrams and descriptions of the refinement programs as well as the restraints they can make use of.

http://reference.iucr.org/dictionary/R_factor - goes into detail about what the R-factor means and what calculations are required to obtain it.

http://ccp4wiki.org/~ccp4wiki/wiki/images/f/fa/Winn-Oulu08-tls.pdf - explains the purpose of TLS and the procedures taken and the software used. It also provides information on the outputs of TLS refinement.