Some form of BMG - the English magazine for Banjo, Mandolin and Guitar enthusiasts - was published from the early 20th Century until 1979. This archive of magazines has many fascinating articles and is a time capsule of ads and attitudes. Steel guitar shows up more often than you would think, like these cover stories below - all available to download. Link below.
It's a fun trip down musical memory lane and a useful resource.
I downloaded one of these just to have a look. What a treat! The writing is so engaging, and there's so much history in these pages. Thanks for posting this!
Each issue also has music arrangements in (mostly) only standard notation but there are occasional steel guitar tunes as well as guitar, banjo and mandolin music.