Complex sentence: In September 1977 "Flowing Rivers", with another number one single "(Love Is) Thicker Than Water" (also co-written by Gibb and his brother Barry) to support it, quickly became a million selling album.
Split into simpler sentences: In September 1977 "Flowing Rivers", with another number one single "(Love Is) Thicker Than Water", a song co-written by Gibb and his brother Barry. To support it, quickly became a million selling album.