“…There has been quite a large amount of recent work [Nguyen et al, 2010, Liu et al, 2012, Moon and Hero, 2014b, Singh and Póczos, 2014a,b, Krishnamurthy et al, 2014, Moon and Hero, 2014a, Gao et al, 2015a,b, Mukherjee et al, 2015, Moon et al, 2016, Berrett et al, 2016, Gao et al, 2017b, Noshad et al, 2017, Wisler et al, 2017, Singh and Pøczos, 2017, Noshad and Hero III, 2018, Bulinski and Dimitrov, 2018 on practical estimation of nonlinear integral functionals of probability densities, of the form…”