=====Rauchen=====
  * Sanders, Ch.L. and Scott, B.R., 2008. SMOKING AND HORMESIS AS CONFOUNDING FACTORS IN RADIATION PULMONARY CARCINOGENESIS - DOI: 10.2203/dose-response.06-003.Sanders  (siehe O:)
  * [[https://aoemj.biomedcentral.com/track/pdf/10.1186/s40557-016-0092-5?site=aoemj.biomedcentral.com|Noh et al. Annals of Occupational and Environmental Medicine (2016) 28:12 DOI 10.1186/s40557-016-0092-5.]] 
  * [[http://www.nejm.org/doi/full/10.1056/NEJM199009063231003|Janerich et al., 1990. Lung Cancer and Exposure to Tobacco Smoke in the Household]]
  * [[https://aoemj.biomedcentral.com/articles/10.1186/s40557-016-0099-y|Oh et al., 2016. Radon exposure and lung cancer: risk in
nonsmokers among cohort studies]]
  * [[https://aoemj.biomedcentral.com/articles/10.1186/s40557-016-0093-4|Kim et al., 2016. Attributable risk of lung cancer deaths due to indoor radon exposure]]


=====Passivrauchen=====
Under the following link, a report is cited where passive smoking and alpha dose delivery is investigated. I could not find the report itself. (report of the National Research Council (NRC 1991)
https://www.ncbi.nlm.nih.gov/books/NBK233257/        (towards the end)             

A rather short article with the title “Radioactivity and Lung cancer in Active and Passive Smokers”. (1983)
http://journal.chestnet.org/article/S0012-3692(15)37020-3/pdf

Finally, this studies suggest that there may be an increased exposure to radon (resp. radon daughters with tendency to attach to smoke) in presence of tobacco smoke. 
[[https://www.sciencedirect.com/science/article/pii/016041208690005X|study 1]] 
[[http://scholar.google.ch/scholar_url?url=http://www.sjweh.fi/download.php%3Fabstract_id%3D1918%26file_nro%3D1&hl=de&sa=X&scisig=AAGBfm15PkfUWxfZ-aQM6hgpPOlm9ZmPZA&nossl=1&oi=scholarr&ved=0ahUKEwjWwrTYit_ZAhUkJcAKHSy7CjoQgAMILCgBMAA |study 2]]