Referrer requests for application number?

Hi WSO, Some of my referrers, when asked about how exactly will they refer me, asked me to give them the "application number" of my application when I finish applying. They seem to assume that all banks will give out a sort of confirmation number after I apply. However, as I have applied to several BBs' sophomore internships, it seems that only BAML provides an application number. Has anyone encountered a similar situation and does anyone know if it application number can be procured through other ways or is there another way to solve this situation? Thanks