Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Game | Date | Opponent | Result | Bills points | Opponents | Bills first downs | Record | Attendance |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1.0 | Sept. 7 | Miami Dolphins | Win | 17.0 | 7.0 | 22.0 | 1–0 | 79598.0 |
| 2.0 | Sept. 14 | New York Jets | Win | 20.0 | 10.0 | 22.0 | 2–0 | 65315.0 |
| 3.0 | Sept. 21 | at New Orleans Saints | Win | 35.0 | 26.0 | 26.0 | 3–0 | 51154.0 |
| 4.0 | Sept. 28 | Oakland Raiders | Win | 24.0 | 7.0 | 25.0 | 4–0 | 77259.0 |
| 5.0 | Oct. 5 | at San Diego Chargers | Win | 26.0 | 24.0 | 14.0 | 5–0 | 51982.0 |
| 6.0 | Oct. 12 | Baltimore Colts | Loss | 12.0 | 17.0 | 24.0 | 5–1 | 73634.0 |
| 7.0 | Oct. 19 | at Miami Dolphins | Loss | 14.0 | 17.0 | 18.0 | 5–2 | 41636.0 |
| 8.0 | Oct. 26 | New England Patriots | Win | 31.0 | 13.0 | 21.0 | 6–2 | 75092.0 |
| 9.0 | Nov. 2 | Atlanta Falcons | Loss | 14.0 | 30.0 | 20.0 | 6–3 | 57959.0 |
| 10.0 | Nov. 9 | at New York Jets | Win | 31.0 | 24.0 | 17.0 | 7–3 | 45677.0 |
| 11.0 | Nov. 16 | at Cincinnati Bengals | Win | 14.0 | 0.0 | 22.0 | 8–3 | 40836.0 |
| 12.0 | Nov. 23 | Pittsburgh Steelers | Win | 28.0 | 13.0 | 23.0 | 9–3 | 79659.0 |
| 13.0 | Nov. 30 | at Baltimore Colts | Loss | 24.0 | 28.0 | 24.0 | 9–4 | 36184.0 |
| 14.0 | Dec. 7 | Los Angeles Rams | Win | 10.0 | 7.0 | 15.0 | 10–4 | 77133.0 |
| 15.0 | Dec. 14 | at New England Patriots | Loss | 2.0 | 24.0 | 28.0 | 10–5 | 58324.0 |
| 16.0 | Dec. 21 | at San Francisco 49ers | Win | 18.0 | 13.0 | 16.0 | 11–5 | 37476.0 |
Question:
Which date did the oakland raiders play as the opponent when the Bills first downs were under 28?
Answer:
Sept. 28