Spectral parameter power series method for discontinuous coefficients
  Let (a,b) be a finite interval and 1/p, q, r be functions from L1(a,b). We show that a general solution (in the weak sense) of the equation (pu')'+qu = zru on (a,b) can be constructed in terms of power series of the spectral parameter z. The series converge uniformly on [a,b] and the corresponding coefficients are constructed by means of a simple recursive procedure. We use this representation to solve different types of eigenvalue problems. Several numerical tests are discussed. 
Herminio Blancarte, Hugo M. Campos, Kira V. Khmelnytskaya
math-ph math.CA math.MP