Que fonte tem um vencedor de corrida de Ben Adriaenssen / Ben van den Bogaart, e o vencedor do GP de Ben Adriaenssen / Ben van den Bogaart, para a data de 1 de abril?
CREATE TABLE table_name_8 (source VARCHAR, date VARCHAR, race_winners VARCHAR, gp_winner VARCHAR)
SELECT source FROM table_name_8 WHERE race_winners = "ben adriaenssen / ben van den bogaart" AND gp_winner = "ben adriaenssen / ben van den bogaart" AND date = "1 april"