Ksh. Anand  Singh, 
    Nonparametric Estimation of Survivorship Function using Retrospective Data on Duration of Breastfeeding-A Smoothing Technique,
    Journal of Modern Mathematics and Statistics,
    Volume 8,Issue 1,
    2014,
    Pages 14-18,
    ISSN 1994-5388,
    jmmstat.2014.14.18,
    (https://makhillpublications.co/view-article.php?doi=jmmstat.2014.14.18)
    Abstract: Retrospectively reported data on duration of breastfeeding 
  often exhibit concentration of points at multiples of 6 or 12 months. As a result, 
  the estimated survivorship function shows jumps at these points. Appropriate 
  statistical methods are necessarily called for obtaining the smooth estimates 
  of the curve. A nonparametric regression smoother, popularly known as loess 
  (locally weighted linear regression smoother has been used here to obtain the 
  smooth estimates. The proposed method is applied to duration data of the 6 states 
  of North East India.
    Keywords: Survivorship function;smooth estimates;nonparametric regression smoother;loess;India