Please cite PISA for all results obtained from this service, should these results be published in any form or otherwise presented.
PISA should be referenced as:

'Protein interfaces, surfaces and assemblies' service PISA at the European Bioinformatics Institute. (,
paper E. Krissinel and K. Henrick (2007). 'Inference of macromolecular assemblies from crystalline state.'. J. Mol. Biol. 372, 774--797.

This document represents the original version of the paper, which includes details which were removed on request of the referee. This contains a more detailed description of the method and an extended discussion.

The previous "official" citation of PISA: paper E. Krissinel and K. Henrick (2005). Detection of Protein Assemblies in Crystals. In: M.R. Berthold (Eds.): CompLife 2005, LNBI 3695, pp. 163--174. Springer-Verlag Berlin Heidelberg.

This document contains some algorithmic details not mentioned in the main publication. The following study contains analysis of PISA results and discusses the limits of their applicability. It gives details of the relationship between complexes in crystals and solution and discusses of whether or not the crystals may lie to us:

paper E. Krissinel (2009). Crystal contacts as nature's docking solutions. J Comput Chem. 2010 Jan 15;31(1):133-43.; DOI 10.1002/jcc.21303