L. A. Romero, "Perturbation theory for polynomials", Lecture Notes, University of New Mexico (2013). math.unm.edu [online]. [cit. 2023-06-28]. Dostupné v archivu pořízeném z originálu dne 2018-04-17.
web.archive.org
L. A. Romero, "Perturbation theory for polynomials", Lecture Notes, University of New Mexico (2013). math.unm.edu [online]. [cit. 2023-06-28]. Dostupné v archivu pořízeném z originálu dne 2018-04-17.
worldcat.org
BENDER, Carl M., 1999. Advanced mathematical methods for scientists and engineers I : asymptotic methods and perturbation theory. New York, NY: [s.n.]. Dostupné online. ISBN978-1-4757-3069-2. OCLC851704808