Garcia-Esteve L, Navarro P, Ascaso C, Torres A, Aguado J, Gelabert E, Martin-Santos R. Family caregiver role and premenstrual syndrome as associated factors for postnatal depression. Arch Womens Ment Health. 2008 Jul;11(3):193-200.
Parsley (Edwards) TL. Review of the phantom respondents: opinion surveys and political representation. J Off Stat. 1994;10(3):351-5.