Gignac MA, Badley EM, Lacaille D, Cott CC, Adam P, Anis AH. Managing arthritis and employment: making arthritis related work changes as a means of adaptation. Arthritis Rheum 2004;51:909–16.
http://www.ncbi.nlm.nih.gov/pubmed/15593110
WALS description refers back to this reference, though in this reference WALS has not been yet developed in its current form
Gignac MA. Arthritis and employment: an examination of behavioral coping efforts to manage workplace activity limitations. Arthritis Rheum 2005;53:328–36.
http://www.ncbi.nlm.nih.gov/pubmed/15934119
WALS description refers back to this reference, though in this reference WALS has not been yet developed in its current form
http://www.ncbi.nlm.nih.gov/pubmed/22588755
Tang et al. (2011): Measures of work disability and productivity: Rheumatoid Arthritis Specific Work Productivity Survey (WPS-RA), Workplace Activity Limitations Scale (WALS), Work Instability Scale for Rheumatoid Arthritis (RA-WIS), Work Limitations Questionnaire (WLQ), and Work Productivity and Activity Impairment Questionnaire (WPAI).