Literature
Generalized additive models: an introduction with R 2nd ed., Boca Raton: CRC Press / Taylor & Francis Group.
, 2017. Soap Film Smoothing. Journal of the Royal Statistical Society. Series B (Statistical Methodology), 70(5), pp.931-955. Available at: https://www.jstor.org/stable/20203864?seq=1.
, 2008.