ISBN 9780387905426 books & textbook
Sturmian Theory for Ordinary Differential Equations (Applied Mathematical Sciences, 31)
Reid, William T. Burns, J. Herdman, T. Ahlbrandt, C.
Springer /1981-02-20 Paperback / 576 Pages
isbn-10: 0387905421 / isbn-13: 9780387905426