In Pascal, a computer language from N. Wirth from the early 70s, there were two ways you could get a variable into a function, you could pass it by reference or you could pass it by value. "By value" meant that you made a complete copy of the variable and sent that copy to the function so that the original was untouched. "By reference" meant that you passed a pointer (a location indicator, an address) to the function which then proceeded to work on the original variable itself.

In your case, it sounds like they are passing a pointer out to the recipients so that they can make changes directly to the original document.

If you can find some info about Pascal by Niklaus Wirth in German, you may find your exact phrase.

Good luck.