Reading: Slaughterhouse-Five

A few days ago, I finished reading Kurt Vonnegut's Slaughterhouse-Five.

I haven't read a lot of Vonnegut's novels, so I was surprised to find the character of Kilgore Trout whom I remembered from Breakfast of Champions. Curious about this connection, and whether the character occurs elsewhere in Vonnegut's writings, I did some searching and found that there was also a connection with The Sirens of Titan - the distant planet Tralfamadore (I thought that name sounded familiar).

Now I'm wondering if there are other connections across his writings...