Charm counting in $Z \to b\overline{b}$ decays

The inclusive production of charmed particles in Z^0 -> bb decays has been measured selecting D^0,D^+, D^+_s and Lambda_c decays on a high b purity sample of data collected by ALEPH between 1992 and 1995. All the weak decaying charmed final states, but the strange charmed baryons, have been measured allowing the inclusive determination of the average number of charm quark per b decay n_c.