1. N. Bebiano, C.K. Li and J. da Providencia, Generalized numerical ranges of permanental compounds arising from quantum systems of bosons, Electronic Linear Algebra 7 (2000), 73-91.
2. W. Grueb, Multilinear Algebra, 2nd ed., Springer-Verlag, New York, 1978.
3. E. Majorana, Atomi orientati in campo magnetico variabile, Il Nuovo Cimento 9.1 (1932), 43-50.
4. M. Marcus, Finite Dimensional Multilinear Algebra, Part I, Marcel Dekker, New York, 1973.
5. H. Minc, Permanents. Encyclopedia of Mathematics and its Applications. Addison-Wesley, Boston 1978.