linking Iterators together in this manner is more efficient (and convenient) than reading out the contents of each Iterator into a List and creating a new Iterator.
W. Ferreira, J. de Sousa, J. Freire, G. Farias, and V. Freire. BRAZILIAN JOURNAL OF PHYSICS, 36 (2A):
438-439(2006)12th Brazilian Workshop on Semiconductor Physics (BWSP-12), Sao Jose dos
Campos, BRAZIL, APR 04-08, 2005.