Bond JC, Geller RJ, White KO, Hatch EE, Rothman KJ, Wise LA. Concordance of self-reported sexual intercourse frequency between members of mixed-sex couples attempting conception. Can J Hum Sex. 2022 Dec;31(3):342-53. doi: 10.3138/cjhs.2021-0059
Kjeldsen BJ, Thorsen H, Whalley D, Kronborg O. Influence of follow-up on health-related quality of life after radical surgery for colorectal cancer. Scand J Gastroenterol. 1999 May;34(5):509-15.