Stochastic realization of finite-valued processes and primes in the positive matrices / G. PicciA partial classification of primes in the positive matrices and in the doubly stochastic matrices / G. Picci, J.M. van den Hof, J.H. van SchuppenPrimes in the doubly stochastic circulants / G. Picci, J.M. van den Hof, J.H. van SchuppenOn the weak finite stochastic realization problem / G. Picci & J.H. van Schuppen