Here is a little videoguide showing how to get 2-4 magazines in one go. To the date, these four always respawn in the same place.
Notice that after taking the first magazine, I go behind the cabin and look to a pile of wood logs. Here sometimes lies the second magazine. Take a look just in case there it is if you do this tour.
Notice, the servers are public. If some other player has already taken the magazines, they will not respawn after a long time, so if you dont find them, wait while you do other things (Missions, etc) or exit and re enter in hopefully another server.
I take credit for the video
Edit 1: You dont have to "read" them in order for the trophy to count. Taking them counts towards it. Also, it doesn't count if another player drops or sell them to you.