Expansions of solutions of higher order evolution equations in series of generalized heat polynomials. Hile, G.N.; Stanoyevitch, Alexander — 2002 Electronic Journal of Differential Equations (EJDE) [electronic only]
The Relative Spectrum of Elements in a Real Banach Algebra. G.N. Hile; W.E. Pfaffenberger — 1980 Mathematische Annalen