1. Real Analysis;Bruckner,2008
2. Weyl–Titchmarsh theory for Sturm–Liouville operators with distributional potentials;Eckhardt;Opuscula Math.,2013
3. Real analysis;Folland,1999
4. Finite Differences and Difference Equations in the Real Domain;Fort,1948
5. Generalized functions. Vol. 1;Gel′fand,1964