Guidelines for controlled trials of drugs in tension-type headache: second edition

L Bendtsen, M E Bigal, R Cerbo, H C Diener, K Holroyd, C Lampl, D D Mitsikostas, T J Steiner, P Tfelt-Hansen, International Headache Society Clinical Trials Subcommittee, L Bendtsen, M E Bigal, R Cerbo, H C Diener, K Holroyd, C Lampl, D D Mitsikostas, T J Steiner, P Tfelt-Hansen