1
Merriam-Webster.
| Merriam-Webster, Incorporated |
1989
제적자료
2
Merriam-Webster.
| Merriam-Webster, Incorporated |
1984
제적자료
3
Merriam Webster
| Merriam-Webster, Incorporated |
1988
제적자료
5
Soukhanov, Anne H.
| Merriam-Webster, Incorporated |
1993
보존자료