{{Cite journal| doi = 10.3390/ijerph18094543| volume = 18| issue = 9| last1 = Fiok| first1 = K.| last2 = Karwowski| first2 = W.| last3 = Gutierrez| first3 = E.| last4 = Saeidi| first4 = M.| last5 = Aljuaid| first5 = A.M.| last6 = Davahli| first6 = M.R.| last7 = Taiar| first7 = R.| last8 = Marek| first8 = T.| last9 = Sawyer| first9 = B.D.| title = A study of the effects of the covid-19 pandemic on the experience of back pain reported on twitter® in the united states: A natural language processing approach| journal = International Journal of Environmental Research and Public Health| date = 2021}}