Complex sentence: Leaf only went on to produce one more set, however Bowman continued until 1955, when they were bought out by the Topps Chewing Gum Company in 1956.
Split into simpler sentences: Leaf only went on to produce one more set, however Bowman continued producing sets through 1955. Bowman was bought out by the Topps Chewing Gum Company in 1956.