Context: CREATE TABLE table_16527640_2 (vfl_club_s_ VARCHAR, rank_held_at_time_of_death VARCHAR)
Question: What vfl club(s) for players ranked sergeant, 8th brigade australian field artillery at time of death?
Answer: SELECT vfl_club_s_ FROM table_16527640_2 WHERE rank_held_at_time_of_death = "Sergeant, 8th Brigade Australian Field Artillery"