You may think you've seen this cover before, and you could bet your Fingers of Fear and Avenging Spirit that you have... but Panico #2 from 1978 came in first, courtesy of Vilmar ... and if you spend a bit of time browsing http://www.tebeosfera.com/ you will find many such samples of original sources of Gredown covers and reprint material.
I've made a start on matching many of the covers on this site to the Australian issues... It's easy to get lost on this site given both the wealth of material and the translation hurdles... But for the willing and patient, there's plenty of information on issues, artists and writers, cover artists, contents... I say roll up your sleeves, bookmark your favourite online translator (I've been using http://www.translate.google.com/), and get stuck into it, fellow Gredownphiles!