| RefNo | Title | Date |
| IM/004475 | Sykes, Sir Charles | nd |
| IM/004476 | Sykes, Sir Charles | nd |
| RR/70/55 | Letter from Charles Sykes, on a paper 'The thermal etching of silver' by B Chalmers, R King and R Shuttleworth | 12 January 1948 |
| RR/70/33 | Referee's report by Charles Sykes, on a paper 'On the inhomogeneity of plastic deformation in the crystals of an aggregate' by W Boas and M E Hargreaves | 1947 |
| RR/64/73 | Referee's report by Henry Cort Harold Carpenter, on a paper 'The superlattice in ß Brass' by Frederic Wood Jones and Charles Sykes | [May 1937] |
| RR/65/255 | Referee's report by Henry Cort Harold Carpenter, on a paper 'Specific heat-temperature curves of some age-hardening alloys' by N Swindells and Charles Sykes | 1938 |
| RR/67/66 | Letter from J D Griffith Davies, Assistant Secretary of the Royal Society, on a paper 'Precipitation in the alloys of copper and silver' by Charles Sykes and W F Cox to William Lawrence Bragg | 6 February 1940 |
| RR/68/92 | Referee's report by William Hume-Rothery, on a paper 'Precipitation in single crystals of silver-rich and copper-rich alloys of the silver-copper system' by Frederic Wood Jones, C M Leech and Charles Sykes | 21 January 1942 |
| RR/69/261 | Referee's report by Cecil Henry Desch, on a paper 'The intermetallic compound phases of the system aluminium-manganese-zinc' by G V Raynor, D W Wakeman and Charles Sykes | 1946 |
| RR/70/146 | Referee's report by Charles Sykes, on three papers 'Binary and ternary interstitial alloys. Parts I, II and III' by Kenneth Henderson Jack | 1947 |
| RR/70/145 | Letter from Charles Sykes, on three papers 'Binary and ternary interstitial alloys. Parts I, II and III' by Kenneth Henderson Jack to David Christie Martin, Assistant Secretary of the Royal Society | 16 April 1948 |
| RR/69/111 | Referee's report by Charles Sykes, on a paper 'The statistical aspect of fatigue of materials' by A M Freudenthal | 1946 |
| RR/69/31 | Referee's report by Charles Sykes, on a paper 'The anisotropy of thermal expansion as a cause of deformation in metals and alloys' by W Boas and Robert William Kerr Honeycombe | 1946 |
| EC/1943/16 | Sykes, Sir Charles: certificate of election to the Royal Society | |
| RR/70/54 | Referee's report by Charles Sykes, on a paper 'The thermal etching of silver' by B Chalmers, R King and R Shuttleworth | 1947 |
| RR/67/71 | Letter from William Lawrence Bragg, on a paper 'Precipitation in the alloys of copper and silver' by Charles Sykes and W F Cox to J D Griffith Davies, Assistant Secretary of the Royal Society | 14 March 1940 |
| PB/1/33/3/7 | Companion of Honour | 1965 |
| RR/62/39 | Referee's report by Cecil Henry Desch, on a paper 'The atomic rearrangement process in the copper-gold alloy Cu3Au' by Charles Sykes and Frederic Wood Jones | [June 1936] |
| RR/67/72 | Referee's report by William Hume-Rothery, on a paper 'Precipitation in the alloys of copper and silver' by Charles Sykes and W F Cox | March 1940 |
| RR/51/93 | Referee's report by Henry Cort Harold Carpenter, on a paper 'Some peculiarities in the physical properties of iron-aluminium alloys' by Charles Sykes and H Evans | [January 1934] |
| RR/54/132 | Referee's report by Cecil Henry Desch, on a paper 'Methods for investigating thermal changes occuring during transformations in a solid solution' by Charles Sykes | September 1934 |
| RR/67/64 | Letter from Charles Sykes, on his paper with W F Cox 'Precipitation in the alloys of copper and silver' to William Lawrence Bragg | 31 January 1940 |
| RR/67/65 | Letter from William Lawrence Bragg, on a paper 'Precipitation in the alloys of copper and silver' by Charles Sykes and W F Cox to Alfred Charles Glyn Egerton | 2 February 1940 |
| RR/67/67 | Memorandum from J D Griffith Davies, Assistant Secretary of the Royal Society, on a paper 'Precipitation in the alloys of copper and silver' by Charles Sykes and W F Cox to Henry Lewis Guy | 12 February 1940 |
| RR/67/68 | Letter from William Lawrence Bragg, on a paper 'Precipitation in the alloys of copper and silver' by Charles Sykes and W F Cox to J D Griffith Davies, Assistant Secretary of the Royal Society | 17 February 1940 |
| RR/67/69 | Letter from J D Griffith Davies, Assistant Secretary of the Royal Society, on a paper 'Precipitation in the alloys of copper and silver' by Charles Sykes and W F Cox to William Lawrence Bragg | 12 March 1940 |
| RR/67/70 | Letter from Charles Sykes, on his paper with W F Cox 'Precipitation in the alloys of copper and silver' to William Lawrence Bragg | 13 March 1940 |