I’ve especially appreciated finding covers that feature initials and names. Perhaps not surprisingly, this tradition seems to have fallen off after the 1950s. During this project’s next phase, I hope to research the histories of these manufacturers, and add them to this site. Here, in addition to A.M., which we’ve seen on several covers, the initials H.Q.L. perhaps stand for “HochQuelleLeitung” – the high water line that provides Vienna with 40% of its water.