Tuuli A. Lahti; Sami Leppämäki; Jouko Lönnqvist; Timo Partonen (2006). «Transition to daylight saving time reduces sleep duration plus sleep efficiency of the deprived sleep». Neuroscience Letters406 (3): 174-177. PMID16930838. doi:10.1016/j.neulet.2006.07.024.
Tuuli A. Lahti; Sami Leppämäki; Jouko Lönnqvist; Timo Partonen (2006). «Transition to daylight saving time reduces sleep duration plus sleep efficiency of the deprived sleep». Neuroscience Letters406 (3): 174-177. PMID16930838. doi:10.1016/j.neulet.2006.07.024.