Comparison of symptoms experienced by users of analogue and digital mobile phones: a Swedish-Norwegian epidemiological study.

Haugsdal B, Hauger E, Mild KH, Oftedal G, Sandstrom M, Wilen J, Tynes T

Arbetslivsrapport 23: 1998

Study of mobile phone users showed a statistically significant association between calling time/number of calls per day and the prevalence of warmth behind/around the ear, headaches, and fatigue.