(VAR x y z)
(RULES 
bsort(nil) -> nil
bsort(.(x,y)) -> last(.(bubble(.(x,y)),bsort(butlast(bubble(.(x,y))))))
bubble(nil) -> nil
bubble(.(x,nil)) -> .(x,nil)
bubble(.(x,.(y,z))) -> if(<=(x,y),.(y,bubble(.(x,z))),.(x,bubble(.(y,z))))
last(nil) -> 0
last(.(x,nil)) -> x
last(.(x,.(y,z))) -> last(.(y,z))
butlast(nil) -> nil
butlast(.(x,nil)) -> nil
butlast(.(x,.(y,z))) -> .(x,butlast(.(y,z)))
)
(COMMENT Example 4.61 (Bubble-Sort) in \cite{SK90})