@article {Helliwell214, author = {Philip S Helliwell and GRAPPA Group}, title = {GRAPPA--Group for Research and Assessment of Psoriasis and Psoriatic Arthritis, Stockholm, May/June 2006.}, volume = {34}, number = {1}, pages = {214--219}, year = {2007}, publisher = {The Journal of Rheumatology}, issn = {0315-162X}, URL = {https://www.jrheum.org/content/34/1/214}, eprint = {https://www.jrheum.org/content/34/1/214.full.pdf}, journal = {The Journal of Rheumatology} }