For the purpose of avoidance of double taxation, Article XV provides that, on the part of the United States, there shall be allowed against the United States income tax a credit for the amount of Danish taxes described in Article I of the convention imposed on income derived from sources within Denmark for taxable years beginning on and after January 1, 1948. Such credit, however, is subject to the limitations provided in section 131 of the Internal Revenue Code (relating to the credit for foreign taxes). See §§29.131-1 to 29.131-10 of Regulations 111 (26 CFR 1949 ed. Supps. 29.131-1 to 29.131-10) [and §§39.131(a)  1 to 39.131(j)-1 of Regulations 118 (26 CFR, Rev. 1953, Parts 1-79, and Supps.)].