We study the magneto-transport in vertical quantum dots both theoretically
and experimentally. We focus our attention on the non-linear transport regi
me. We demonstrate that the peak amplitudes in the I-V characteristics show
a dramatically different behaviour as a function of the magnetic field, de
pending on the value of the angular momemtum of the dot state through which
tunnelling occurs. The investigation allows us to probe details of the qua
ntum dot wavefunctions and to distinguish tunnelling through localised stat
es related to impurities or to quantum dots.