Physical Activity through Sustainable Transport Approaches (PASTA): protocol for a multi-centre, longitudinal study. - Dons, Evi; Götschi, Thomas; Nieuwenhuijsen, Mark; de Nazelle, Audrey; Anaya, Esther; Avila-Palencia, Ione; Brand, Christian; Cole-Hunter, Tom; Gaupp-Berghausen, Mailin; Kahlmeier, Sonja; Laeremans, Michelle; Mueller, Natalie; et al. (BMC Public Health, 2015)