Bartle 1995,第xii+179頁. Bartle, Robert G. The elements of integration and Lebesgue measure. Wiley Classics Library. New York: John Wiley & Sons Inc. 1995. xii+179. ISBN 0-471-04222-6. MR 1312157.
要以狄拉克符號來表達這一節的內容,可見Levin 2002,Coordinate-space wave functions and completeness, pp.=109ff Levin, Frank S., Coordinate-space wave functions and completeness, An introduction to quantum theory, Cambridge University Press: 109ff, 2002, ISBN 0-521-59841-9
Fourier 1822,第408頁. Fourier, J.B. The Analytical Theory of Heat English translation by Alexander Freeman, 1878. The University Press. 1822: 408 [2016-12-08]. (原始内容存档于2021-04-19)., cf p 449 and pp 546–551. 法文原始文本请参见这里 (页面存档备份,存于互联网档案馆)
參見:Laugwitz 1989 Laugwitz, D., Definite values of infinite sums: aspects of the foundations of infinitesimal analysis around 1820, Arch. Hist. Exact Sci., 1989, 39 (3): 195–245, doi:10.1007/BF00329867
Laugwitz 1989,第230頁. Laugwitz, D., Definite values of infinite sums: aspects of the foundations of infinitesimal analysis around 1820, Arch. Hist. Exact Sci., 1989, 39 (3): 195–245, doi:10.1007/BF00329867
Fourier 1822,第408頁. Fourier, J.B. The Analytical Theory of Heat English translation by Alexander Freeman, 1878. The University Press. 1822: 408 [2016-12-08]. (原始内容存档于2021-04-19)., cf p 449 and pp 546–551. 法文原始文本请参见这里 (页面存档备份,存于互联网档案馆)