@article {9868,
	title = {Electron dynamics in slowly modulated crystals: Theorems of power and adiabatic drifting},
	journal = {Physica E: Low-Dimensional Systems and Nanostructures},
	year = {2001},
	pages = {327-332},
	doi = {10.1016/S1386-9477(00)00223-X},
	author = {Qian Niu and Ganesh Sundaram}
}
