How effective is topical fluorouracil to treat facial superficial basal cell carcinoma (BCC)?

I wonder how effective topical fluorouracil is to treat facial superficial basal cell carcinoma (BCC).

What I have found so far doesn’t give any source supporting their claims or I cannot access them:

https://bpac.org.nz/2017/skin-cancer.aspx:

Apply twice daily, for six to 12 weeks; N.B. Fluorouracil is generally only used to treat small, very superficial BCC, and treatment is associated with a high rate of recurrence

https://www.drugs.com/monograph/fluorouracil-topical.html#ra:

Used topically for the treatment of superficial basal cell carcinoma when conventional methods are impractical (e.g., in patients with multiple lesions or difficult treatment sites).a b g Efficacy not established for treatment of other basal cell carcinomas; establish diagnosis before initiating treatment. [references a b g]

When lesions are isolated and easily accessible, conventional techniques (e.g., surgery, curettage and dessication, cryotherapy) are preferred because they have a higher response rate. [references a b g]

(I don’t have access to references a b g)

{1,2} focus on actinic keratoses, e.g. from {2}:

The results of this meta-analysis show that both imiquimod and 5-fluorouracil are effective methods for the treatment of actinic keratosis and provide a useful alternative to cryotherapy. However, this analysis suggests that imiquimod may have higher efficacy than 5-fluorouracil for actinic keratosis lesions located on the face and scalp and therefore provides another option to dermatologists.

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References:

• {1} Tanghetti, Emil, and Philip Werschler. "Comparison of 5% 5-fluorouracil cream and 5% imiquimod cream in the management of actinic keratoses on the face and scalp." Journal of drugs in dermatology: JDD 6, no. 2 (2007): 144-147. https://pubmed.ncbi.nlm.nih.gov/17373172/
• {2} Gupta, Aditya K., Valerie Davey, and Heather Mcphail. "Evaluation of the effectiveness of imiquimod and 5-fluorouracil for the treatment of actinic keratosis: Critical review and meta-analysis of efficacy studies." Journal of cutaneous medicine and surgery 9, no. 5 (2005): 209-214. https://pubmed.ncbi.nlm.nih.gov/16502198/