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
Kim D, Lauria DT, Poulos C, Dong B, Whittington D. Effect of travel distance on household demand for typhoid vaccines: implications for planning. Int J Health Plann Manage. 2013 Mar 12;Advance Online.