Which docbook element to use for a mathematical formula explanation?

[Erik Leunissen <e.leunissen@hccnet.nl>]

Hi all,

Many scientific or technical documents explain mathematical formulae 
like in the following example (only fixed width fonts will display this 
example as intended):



               V = I*R	            (1)


where:    V = voltage (volt)
          I = current (ampere)
          R = resistance (ohm)



My question concerns the latter part, from 'where:' onwards, which 
explains the symbols.

What docbook element(s) would you recommend for implementing such an 
explanation (maybe considering that it's meant for print output, PDF)?

Thanks for any advice,

Erik Leunissen.