Complex sentence: The convention was first invented Jack Marx, and independently by Stayman's regular partner, George Rapee, but first published by Stayman in an article that he wrote in Bridge World magazine in 1945.
Split into simpler sentences: The convention was in fact invented (independently) by Jack Marx and by Stayman's regular partner, George Rapee. It was first published by Stayman, however, in an article he wrote for the Bridge World magazine in 1945.