I have found several relevant links.

For the ‘randomized controlled trial investigating topical cannabidiol for thumb basal joint arthritis,’ I’ll use (PubMed article `J Hand Surg Am. 2022 Jul;47(7):611-620. doi: 10.1016/j. jhsa. 2022.03. 002. Epub 2022 May 28.`).

For ‘comprehensive reviews of preclinical and clinical studies… anti-inflammatory and analgesic properties of topical CBD,’ I can use:

1. ‘Cannabidiol (CBD): A Systematic Review of Clinical and Preclinical Evidence in the Treatment of Pain’ (PMC – PubMed Central)
2. ‘Transdermal Delivery of Cannabidiol for the Management of Acute Inflammatory Pain: A Comprehensive Review of the Literature’ (MDPI)

I need to make sure I don’t use more than 5 authoritative external links. I have 3 good ones already. I will just stick to these 3 to avoid over-sourcing and ensure deep integration.