'Hierarchical Bases' (Electromagnetic Waves, 2015), 'Higher-order Techniques in Computational Electromagnetics', Chap. 5, pp. 183-270, DOI: 10.1049/SBEW507E_ch5 IET Digital Library, https://digital-library.theiet.org/;jsessionid=bkmhiintt0b56.x-iet-live-01content/books/10.1049/sbew507e_ch5