| RefNo | Title | Date |
| EC/1907/18 | Young, William Henry: certificate of election to the Royal Society | |
| RR/16/245 | Referee's report by Henry Frederick Baker, on a paper 'The general theory of integration' by Dr William Henry Young | 2 December 1904 |
| MDA/A/22/101 | Postcard from William Henry Young to Albert C Seward, Villa Cottage, La-Suisse | 1 August 1940 |
| NLB/48/100 | Copy letter from Robert William Frederick Harrison, to Professor [William Henry] Young, Fellow of the Royal Society, Geneva | 16 May 1913 |
| NLB/54/132 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to Sir [James Hopwood] Jeans, Chairman of the Mathematics Committee and FRS | 13 February 1917 |
| NLB/35/804 | Copy letter from Robert William Frederick Harrison, to Dr William Henry Young, Fellow of the Royal Society | 17 July 1907 |
| NLB/36/619 | Copy letter from Robert William Frederick Harrison, to Dr William Henry Young, Fellow of the Royal Society | 20 November 1907 |
| NLB/46/552 | Copy letter from Robert William Frederick Harrison, to Dr [William Henry] Young, Fellow of the Royal Society | 24 September 1912 |
| NLB/48/370 | Copy letter from Robert William Frederick Harrison, to Professor [William Henry] Young, Fellow of the Royal Society | 23 June 1913 |
| NLB/48/143 | Copy letter from Robert William Frederick Harrison, to Professor [William Henry] Young, Fellow of the Royal Society, Geneva | 23 May 1913 |
| NLB/48/417 | Copy letter from Robert William Frederick Harrison, to Professor [William Henry] Young, Fellow of the Royal Society | 1 July 1913 |
| NLB/50/516 | Copy letter from Robert William Frederick Harrison, to Professor [William Henry] Young, Fellow of the Royal Society, La Nouette de la Foret, Geneva | 23 July 1914 |
| NLB/52/229 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to Mrs Chisholm Young; Epinettes 22, Lausanne, Switzerland | 19 October 1915 |
| NLB/52/433 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to Professor Alfred North Whitehead, Chairman of the Sectional Committee for Maths and FRS | 7 December 1915 |
| NLB/54/223 | Copy letter from Joseph John Thomson, President of the Royal Society; to Professor [William Henry] Young, FRS | 7 March 1917 |
| NLB/54/25 | Copy letter from [Robert William Frederick Harrison, Assistant Secretary of the Royal Society]; to Dr. [William Henry] Young, FRS | 24 January 1917 |
| NLB/54/23 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to Professor [Ernest William] Hobson, FRS | 23 January 1917 |
| NLB/54/428 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to Dr. [William Henry] Young, FRS; Rodline, Lausanne | 11 May 1917 |
| RR/24/98 | Referee's report by Ernest William Hobson, on a paper 'On the series of Legendre' by William Henry Young | [November 1917] |
| NLB/54/54 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to Sir [James Hopwood] Jeans, Chairman of the Mathematics Committee and FRS | 29 January 1917 |
| RR/24/99 | Referee's report by Godfrey Harold Hardy, on a paper 'On the Cesàro convergence of restricted Fourier series' by William Henry Young | [March 1917] |
| RR/24/100 | Referee's report by Godfrey Harold Hardy, on a paper 'On the mode of approach to zero of the coefficients of a Fourier series' by William Henry Young | [March 1917] |
| NLB/61/10 | Copy letter from James Hopwood Jeans, Secretary of the Royal Society; to Professor [William Henry] Young, FRS | 28 April 1921 |
| NLB/54/42 | Copy letter from [Robert William Frederick Harrison, Assistant Secretary of the Royal Society]; to Professor [William Henry] Young, FRS | 27 January 1917 |
| RR/18/194 | Referee's report by Alfred Cardew Dixon, on a paper 'On a mode of generating fourier series' by William Henry Young | May 1911 |
| NLB/53/491 | Copy letter from [Robert William Frederick Harrison], Assistant Secretary of the Royal Society; to Professor [William Henry] Young, FRS, Rodlinde, Lausanne | 12 October 1916 |
| NLB/58/270 | Copy letter from Edwin Deller, Assistant Secretary of the Royal Society; to Professor [William Henry] Young, FRS | 14 April 1920 |
| NLB/59/91 | Copy letter from Edwin Deller, Assistant Secretary of the Royal Society; to Professor [William Henry] Young, FRS | 16 July 1920 |
| NLB/58/452 | Copy letter from Edwin Deller, Assistant Secretary of the Royal Society; to [Messrs Harrison & Sons] | 6 May 1920 |
| NLB/58/525 | Copy letter from Edwin Deller, Assistant Secretary of the Royal Society; to Professor [William Henry] Young, FRS; The University of Aberystwyth; Wales | 17 May 1920 |
| NLB/58/819 | Copy letter from Edwin Deller, Assistant Secretary of the Royal Society; to Professor [William Henry] Young, FRS | 21 June 1920 |
| NLB/59/226 | Copy letter from Edwin Deller, Assistant Secretary of the Royal Society; to Professor [William Henry] Young, FRS | 27 July 1920 |
| NLB/57/275 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to unknown correspondent | 2 October 1919 |
| NLB/59/922 | Copy letter from Edwin Deller, Assistant Secretary of the Royal Society; to Professor [William Henry] Young, FRS | 1 December 1920 |
| RR/19/151 | Referee's report by Ernest William Hobson, on a paper 'On the formation of usually convergent Fourier series' by William Henry Young | nd [1912] |
| RR/25/59 | Referee's report by Ernest William Hobson, on a paper 'On non-harmonic trigonometrical series' by William Henry Young | [April 1918] |
| NLB/57/253 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to the Manager, London County, Westminster & Parr's Bank, Cambridge | 29 September 1919 |
| NLB/68/435 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Professor [William Henry] Young, FRS | 11 July 1925 |
| NLB/61/5 | Copy letter from James Hopwood Jeans, Secretary of the Royal Society; to Professor [Ernest William] Hobson, FRS, and Professor [William Henry] Young, FRS | 26 April 1921 |
| NLB/71/810 | Copy letter from James Hopwood Jeans, Secretary of the Royal Society; to Prof. [William Henry] Young, FRS | 1 November 1928 |
| NLB/69/793 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Prof. [William Henry] Young, FRS | 18 October 1926 |
| NLB/71/958 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Prof. [William Henry] Young, FRS | 17 December 1928 |
| NLB/68/556 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Professor [William Henry] Young, FRS | 7 August 1925 |
| NLB/71/443 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Prof. [William Henry] Young, FRS | 21 May 1928 |
| NLB/70/738 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Professor [William Henry] Young, FRS | 15 July 1927 |
| NLB/71/515 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Prof. [William Henry] Young, FRS | 22 June 1928 |
| NLB/71/405 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Prof. [William Henry] Young, FRS | 3 May 1928 |
| NLB/71/653 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to [John Edensor] Littlewood Esq., FRS | 26 September 1928 |
| NLB/71/819 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Prof. [William Henry] Young | 8 November 1928 |
| NLB/71/779 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Prof. [William Henry] Young, FRS | 31 October 1928 |
| NLB/72/627 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Professor [William Henry] Young, FRS | 31 January 1930 |
| IM/005042 | Young, William Henry | nd |
| NLB/44/90 | Copy letter from Robert William Frederick Harrison to Dr W [William] H [Henry] Young FRS | 3 May 1911 |
| RR/22/135 | Referee's report by Godfrey Harold Hardy, on a paper 'Note on the existence of converging sequences in certain oscillating successions of functions' by William Henry Young | November 1915 |
| RR/19/149 | Referee's report by Godfrey Harold Hardy, on a paper 'On the multiplication of successions of Fourier constants' by William Henry Young | [July 1912] |
| RR/24/97 | Referee's report by Godfrey Harold Hardy, on a paper 'On the series of Legendre' by William Henry Young | [November 1917] |
| RR/16/244 | Referee's report by Ernest William Hobson, on a paper 'The general theory of integration' by William Henry Young | August 1904 |
| RR/19/150 | Referee's report by Godfrey Harold Hardy, on a paper 'On the new theory of integration' by William Henry Young | [January 1913] |
| EC/1907/17 | Young, William Henry: certificate of election to the Royal Society | |
| NLB/54 | New Letter Book volume 54, copy letters sent from Royal Society administration | 10 January 1917-2 November 1917 |
| NLB/71 | New Letter Book volume 71, copy letters sent from Royal Society administration | 1 December 1927-14 January 1929 |
| NLB/52 | New Letter Book volume 52, copy letters sent from Royal Society administration | 9 July 1915-8 March 1916 |