Circulation income.
(iii) Circulation income. The term circulation income means the income attributable to the production, distribution or circulation of a periodical (other than gross advertising income) including all amounts realized from or attributable to the sale or distribution of the readership content of the periodical, such as amounts realized from charges made for reprinting or republishing articles and special items in the periodical and amounts realized from sales of back issues. Where the right to receive an exempt organization periodical is associated with membership or similar status in such organization for which dues, fees or other charges are received (hereinafter referred to as membership receipts), circulation income includes the portion of such membership receipts allocable to the periodical (hereinafter referred to as allocable membership receipts). Allocable membership receipts is the amount which would have been charged and paid if: