For instance, if many entries are from a journal with an abbreviation that may be hard to remember, such as 'J. Theor. Biol.' (Journal of Theoretical Biology), a string named JTB could be defined to represent the journal's name. Instead of repeating the exact journal name in each entry, the characters '#JTB#' (without quotes) are put into the journal field of each, ensuring the journal name is written identically each time.