https://openlibrary.org/books/OL5760644M.opds Advanced engineering mathematics 2022-10-18T07:53:33Z Erwin Kreyszig https://openlibrary.org/authors/OL144195A/Erwin_Kreyszig Wiley New York London Sydney Toronto 1972 xvii, 866 p. 24 x 17 x 4 centimeters 3d ed. Bibliography: p. 789-793. eng https://openlibrary.org/books/OL5760644M https://archive.org/details/advancedengineer00krey urn:ISBN:0471507288 71172951