The system by which Zaire works […] is very simple. Every official you encounter will make life as unpleasant for you as he possibly can until you pay him to stop it. In US dollars. He then passes you on to the next official who will be unpleasant to you all over again.

Douglas Adams (1952-2001) English author, humorist, screenwriter

Last Chance to See, ch. 3 (1990) [with Mark Carwardine]
    (Source)

Though the trip to see the northern white rhino was taken, and the chapter about it is in the book, it was not included in the BBC Radio series (1989).

Adams reading the 1992 audiobook can be heard here.