The composer's signature

The Russian composer Dmitri Shostakovich had a subtile musical signature, which he hid in some of his compositions. He used his initials (written as DSCH) which he translated into the notes D - E♭ - C - B.

After listening for years to Shostakovich's music I found out today how the phrase sounds, simply by playing it on my guitar. I immediately recognized it.

Now I wonder, are there more examples of composers, who put a signature into one ore more of their works...