We analyze the decay modes B0→D∗−D0K+ and B0→D∗−D∗0K+ and, using the available experimental data, we find bounds for the
constants g and h describing the strong coupling of heavy mesons to light
pseudoscalar mesons. Both the decay channels are dominated by broad L=1 charm
resonances; the dominance is effective also in B0→D−D0K+ and B0→D−D∗0K+.Comment: LaTex, 16 pages, 5 figure