  In this contribution we discuss an evaluation of double-nucleon coincidence
spectra for the non-mesonic weak decay of Lambda-hypernuclei. The results have
been obtained by combining a one-meson-exchange model for the Lambda N -> nN
transition in finite nuclei with a Monte Carlo code accounting for the nucleon
final state interactions. A weak-decay-model independent analysis of KEK
coincidence data allows us to extract Gn/Gp values around 0.3-0.4 for
5_Lambda-He and 12_Lambda-C, thus representing an important progress towards
the solution of the Gn/Gp puzzle. Preliminary results for the angular
asymmetries in the non-mesonic weak decay of polarized hypernuclei are also
presented.
