Complex sentence: He was an executive member of the International Council for Friendship and Solidarity with Soviet People and Associate Editor of "Northstar Compass"-the organization's organ publication-which he also wrote articles for and worked on for over 13 years.
Split into simpler sentences: He was an executive member of the International Council for Friendship and Solidarity with Soviet People and Associate Editor of "Northstar Compass"-the organization's organ publication. Stevenson wrote articles for and worked on "Northstar Compass" for over 13 years.