Complex sentence: Reiche was a constant contributor to the newsletters and journals of philatelic organisations, particularly notable was "Postmarked Ottawa" in "The Canadian Philatelist", the official journal of the Royal Philatelic Society of Canada.
Split into simpler sentences: Reiche was a constant contributor to the newsletters and journals of philatelic organisations. Particularly notable was "Postmarked Ottawa" in "The Canadian Philatelist", the official journal of the Royal Philatelic Society of Canada.