Romanus, R. and Ydén, S. 1952. Destructive and Ossifying Spondylitic Changes in Rheumatoid Ankylosing Spondylitis (Pelvo-spondylitis Ossificans). Acta Orthopaedica. 22, 1-4 (Jan. 1952), 88–99. DOI:https://doi.org/10.3109/17453675208988998.