1. A. Berenstein, Group-like elements in quantum groups and Feigin's conjecture, J. Algebra, to appear.
2. A. Berenstein, S. Fomin, A. Zelevinsky, Cluster algebras III: upper bounds and double Bruhat cells, Duke Math. J., to appear.
3. Lectures on Algebraic Quantum Groups;Brown,2002
4. C. De Concini, C. Procesi Quantum Schubert cells and representations at roots of 1, in: Algebraic Groups and Lie Groups, Australian Mathematical Society Lecture Series, vol. 9, Cambridge University Press, Cambridge, 1997, pp. 127–160.
5. V.V. Fock, A.B. Goncharov, Moduli spaces of local systems and higher Teichmuller theory, math.AG/0311149.