The advice provided by Cite Them Right for referencing guidelines is similar to a website, but with the addition of a series or publication number if there is one available.
Author (Year of publication) Title. Series or publication number. Available at: DOI or URL (Accessed: date).
For example;
National Institute for Clinical Excellence (2022) Pembrolizumab for adjuvant treatment of renal cell carcinoma. Nice Technology Appraisal guidance 830. Available at: https://www.nice.org.uk/guidance/ta830 (Accessed: 19th February 2025).