Let $\mathfrak{g}$ be a semisimple Lie algebra over an algebraically closed field. By Harish-Chandra, the center of its universal enveloping algebra $Z(U(\mathfrak{g}))$ is a polynomial ring and the degree of any set of homogeneous generators is uniquely determined.

Where can I find a table describing such generators, e.g. for Lie algebra's of classical type?