Oh don’t be harsh on yourself Denis, nothing wrong with grabbing a PDF to review. Look at it this way, if you find yourself getting enough value out of it maybe then you buy a copy? This is what I tell students at Uni, all of whom know about those sites. I usually learn a few new ones from them. Not sure about Germany but when I do my, ahem, "research", I VPN it all the way. Don’t need to nanny state asking me about my activities on the internet. If I’m feeling particular paranoid, I hop onto the Darkweb. Because they do track this stuff in The UK.