1. WHO Classification of Tumours Online. Available online: 〈https://tumourclassification.iarc.who.int/welcome/〉 (Accessed on Mar 6, 2023).
2. SEER*Stat Software. Available online: 〈https://seer.cancer.gov/seerstat/〉 (Accessed on Mar 22, 2023).
3. RARECARENet – Information Network on Rare Cancers. Available online: 〈http://rarecarenet.istitutotumori.mi.it/rarecarenet/〉 (Accessed on Aug 11, 2021).
4. Ultra-rare sarcomas: a consensus paper from the Connective Tissue Oncology Society community of experts on the incidence threshold and the list of entities;Stacchiotti;Cancer,2021
5. M.B. Amin, AJCC Cancer Staging System Manual, eighth edition, Springer, 2017, ISBN 978-3-319-40617-6.