44-00 General reference works (handbooks, dictionaries, bibliographies, etc.)

44-01 Instructional exposition (textbooks, tutorial papers, etc.)

44-02 Research exposition (monographs, survey articles)

44-03 Historical (must also be assigned at least one classification number from Section 01)

44-04 Explicit machine computation and programs (not the theory of computation or programming)

44-06 Proceedings, conferences, collections, etc.

44Axx Integral transforms, operational calculus {For fractional derivatives and integrals, see <a href="#code:26A33">26A33</a>. For Fourier transforms, see <a href="#code:42A38">42A38</a>, <a href="#code:42B10">42B10</a>. For integral transforms in distribution spaces, see <a href="#code:46F12">46F12</a>. For numerical methods, see <a href="#code:65R10">65R10</a>}

44A05 General transforms [See also <a href="#code:42A38">42A38</a>]

44A12 Radon transform [See also <a href="#code:92C55">92C55</a>]

44A15 Special transforms (Legendre, Hilbert, etc.)

44A40 Calculus of Mikusiński and other operational calculi

44A99 None of the above, but in this section

45-00 General reference works (handbooks, dictionaries, bibliographies, etc.)

45-01 Instructional exposition (textbooks, tutorial papers, etc.)

45-02 Research exposition (monographs, survey articles)

45-03 Historical (must also be assigned at least one classification number from Section 01)

45-04 Explicit machine computation and programs (not the theory of computation or programming)

45-06 Proceedings, conferences, collections, etc.

45A99 None of the above, but in this section

45B99 None of the above, but in this section

45Cxx Eigenvalue problems [See also <a href="#code:34Lxx">34Lxx</a>, <a href="#code:35Pxx">35Pxx</a>, <a href="#code:45P05">45P05</a>, <a href="#code:47A75">47A75</a>]

45C05 Eigenvalue problems [See also <a href="#code:34Lxx">34Lxx</a>, <a href="#code:35Pxx">35Pxx</a>, <a href="#code:45P05">45P05</a>, <a href="#code:47A75">47A75</a>]

45C99 None of the above, but in this section

45Dxx Volterra integral equations [See also <a href="#code:34A12">34A12</a>]