question: Name the sum of Laps for co-drivers of oliver gavin jan magnussen and class of gts with year less than 2004
answer: SELECT SUM(laps) FROM table_name_17 WHERE co_drivers = "oliver gavin jan magnussen" AND class = "gts" AND year < 2004
context: CREATE TABLE table_name_17 (laps INTEGER, year VARCHAR, co_drivers VARCHAR, class VARCHAR)