Horst Jankowski was featured in many radio broadcasts from radio Süddeutscher Rundfunk Stuttgart which I have taped for my collection.
For his discography look here: https://www.discogs.com/artist/59283-Horst-Jankowski
Horst Jankowski is also found on my MPS 2-LP-set "Jazz made in Germany" MPS 0088.053 from 1981. He was member of the Erwin Lehn orchestra at radio Stuttgart (former SDR). Here is the content of that set + a pix from his "Jazztime Stuttgart EP (Bertelsman label) with 4 tracks:
you go to my head / blue moon / There's a small hoterl / basically Jake