I'm sneakily splitting this into two parts so that I can cover the whole weekend while we're moving. The first volume here is from a 1977 run while the remainder are from a series published by Hethke Verlag beginning in 1989. I've only seen up to volume 14 (1992) but the series continued until at least volume 34. The first volume on display (i.e. the second image below) seems not to have been numbered and was published in 1991, reprinting the first Trigan story, but is clearly part of the same series.