Table: us_islands
Columns: rank
island_s_name
area_sqmi
area_km_2
location
population_2000

Question: What is the largest area in Alaska with a population of 39 and rank over 19?
SQL: SELECT MAX("area_km_2") FROM us_islands WHERE "location" = 'alaska' AND "population_2000" = '39' AND "rank" > 19