[1] Usach, I., Martinez, R., Festini, T., & Peris, J. E. (2019). Subcutaneous Injection of Drugs: Literature Review of Factors Influencing Pain Sensation at the Injection Site. Advances in therapy, 36(11), 2986–2996. https://doi.org/10.1007/s12325-019-01101-6
[2] Wright JC, Burgess DJ (29 January 2012). Long acting injections and implants. Springer. p. 114. ISBN 978-1-4614-0554-2.
[3] Sisson H. Aspirating during the intramuscular injection procedure: a systematic literature review. J Clin Nurs. 2015 Sep;24(17-18):2368-75. doi: 10.1111/jocn.12824. Epub 2015 Apr 14. PMID: 25871949.
[4] Chan V O, Colville J, Persaud T, et al. Intramuscular injections into the buttocks: are they truly intramuscular?[J]. European journal of radiology, 2006, 58(3): 480-484.
[5] Zuckerman J. N. (2000). The importance of injecting vaccines into muscle. Different patients need different needle sizes. BMJ (Clinical research ed.), 321(7271), 1237–1238. https://doi.org/10.1136/bmj.321.7271.1237