New solutions to xyz = x+y+z = 1 in integers of quartic fields H. G. Grundman, L. L. Hall (2004) Acta Arithmetica
Non-monogenity of multiquadratic number fields Gábor Nyul (2002) Acta Mathematica et Informatica Universitatis Ostraviensis
Norm form equations and continued fractions. Mollin, R.A. (2005) Acta Mathematica Universitatis Comenianae. New Series