Schulte, K., James, M. A., Tjeng, L. H., Steeneken, P. G., Sawatzky, G. A., Suryanarayanan, R., Dhalenne, G., & Revcolevschi,
A. (2001). Work function changes in the double layered manganite La1.2Sr1.8Mn2O7. Physical Review B, 64(13):, pp. 1-6. doi:10.1103/PhysRevB.64.134428.