THE PROCESS $e^+ e^- \rightarrow l \bar l q \bar q$ AT LEP AND NLC

The cross sections for the reaction $e^+ e^- \rightarrow l \bar l q \bar q $ and for similar four fermion production processes at LEP~1, LEP~2 and the NLC are calculated. Due to the extraordinary symmetry properties of the process, very compact analytical formulae describe the double differential distributions in the invariant masses of the $l \bar l$ and $q \bar{q}$ pairs. The total cross sections may be obtained with two numerical integrations.