Some online journals etc.

The Experimental Music Yearbook "is a repository for composers, performers, and the public to glean the methods and styles of various artists working in the experimental music tradition".

Surround journal.

Ars Acustica – Audio Art – Klangkunst. Issue 4 (October 2012) of Act. Zeitschrift für Musik & Performance.

Electroacoustic Music and Selected Concepts of Radio Art. Free e-book by Michal Rataj.