Packer, R., Shrine, N., Hall, R., Melbourne, C., Thompson, R., Williams, A., Paynton, M., Guyatt, A., Lee, P., John, C., Campbell, A., Hayward, C., de Vries, M., Vonk, J., Davitte, J., Hessel, E., Michalovich, D., Betts, J., Sayers, I., Yeo, A., …Wain, L. Genome-wide association study of chronic sputum production implicates loci involved in mucus production and infection