| Bagley, R. Kelly; Roberts, James S. | Kotoko survey report | 1991 | | Language Assessment, Sociolinguistics |
| Davison, Phil | Batanga survey report | 1991 | | Language Assessment, Sociolinguistics |
| Engelbert, Domche Teko; Hatfield, Deborah H. | Enquête sociolinguistique sur le ghomala'-jo comme dialecte de référence standard | 1991 | | Language Assessment, Sociolinguistics |
| Regnier, Clark D. | Tivoid survey of the Akwaya Sub-division, Manyu Division, Southwest Province | 1991 | | Language Assessment, Sociolinguistics |
| Hasselbring, Sue; Sadembouo, Etienne | A sociolinguistic survey of the Ngemba languages | 1991 | | Language Assessment, Sociolinguistics |
