Axial Involvement in Psoriatic Arthritis cohort (AXIS): the protocol of a joint project of the Assessment of SpondyloArthritis international Society (ASAS) and the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) (2021)
https://pubmed.ncbi.nlm.nih.gov/34987619/

The ASAS-OMERACT core domain set for axial spondyloarthritis (2021)
https://pubmed.ncbi.nlm.nih.gov/34489113/

Data-driven definitions for active and structural MRI lesions in the sacroiliac joint in spondyloarthritis and their predictive utility (2021)
https://pubmed.ncbi.nlm.nih.gov/33523107/