See for example, Gerald B Folland. Convergence and completeness. Fourier Analysis and its Applications Reprint of Wadsworth & Brooks/Cole 1992. American Mathematical Society. 2009: 77 ff [2023-12-24]. ISBN 978-0-8218-4790-9. (原始内容存档于2023-07-26).
See for example, Gerald B Folland. Convergence and completeness. Fourier Analysis and its Applications Reprint of Wadsworth & Brooks/Cole 1992. American Mathematical Society. 2009: 77 ff [2023-12-24]. ISBN 978-0-8218-4790-9. (原始内容存档于2023-07-26).