“…Its properties were further investigated in Bouezmarni and Scaillet (2005), Hagmann and Scaillet (2007), Zhang (2010) and Malec and Schienle (2014). Asymmetric kernel density estimation remains an area of very active research, as the number of recent papers in the area evidences (Kuruwita et al, 2010, Jeon and Kim, 2013, Dobrovidov and Markovich, 2014, Igarashi and Kakizawa, 2014, Hirukawa and Sakudo, 2014, Funke and Kawka, 2015, Markovich, 2015, Hoffmann and Jones, 2015, Funke and Hirukawa, 2016, Igarashi, 2016, Markovich, 2016, Rosa and Nogueira, 2016, Balakrishna and Koul, 2017. Hirukawa and Sakudo (2015) describe a family of 'generalised Gamma kernels' which includes a variety of similar asymmetric kernels in an attempt to standardise those results.…”