http://www.leyhunters.co.uk/sub3.html
has a decent starting bibliography.
I was able to buy originals for my collection on ebay very cheaply - just pennies above the cost of postage in some case - by dint of having a search set up on "earth mysteries". There will be months of nothing and then someone decides to clear out a cupboard
Source, a newsletter on wells, springs etc was sadly shortlived. But a couple of years ago someone digitised them and made them available on line. Can't find them at the moment so I hope they haven't gone again.
The Company of the Green Man, which has wider interestes in terms of sculpture, continuity, folklore etc has just managed to scan in the newsletters from 1998-2005. Then there was a hiatus. 2009-2014 were published electronically anyway.
Joining the COTGM is free I think. You may have to pay for access to the scans of the earlier stuff (I think it wrecked the scanner!)
If you're interested I can pull out a list of newsletter publications from my own bibliographies? I'm not sure how many of them there are but it's just a matter of me reading down a list of publications.
I love this stuff. I don't believe the earth mysteries stuff but that doesn't stop it being true, if you see what I mean :spinning