| RefNo | Title | Date |
| EC/1911/08 | Lang, William Henry: certificate of election to the Royal Society | |
| NLB/13/510 | Copy letter from Robert William Frederick Harrison, to William Henry Lang, [Fellow of the Royal Society], 40 Lawrence Street, Dowan Hill, Glasgow | 2 October 1896 |
| NLB/13/555 | Copy letter from Robert William Frederick Harrison, to William Henry Lang, [Fellow of the Royal Society], 40 Lawrence Street, Dowanhill, Glasgow | 7 October 1896 |
| NLB/13/777 | Copy letter from Robert William Frederick Harrison, to Dr Dukinfield Henry Scott, Fellow of the Royal Society | 23 November 1896 |
| RR/19/47 | Referee's report by William Henry Lang, on a paper 'An investigation into the life-history of cladothrix dichotoma (Cohn)' by David Ellis | [March 1912] |
| RR/25/3 | Referee's report by William Henry Lang, on a paper 'On the occurrence of multinucleate cells vegetative tissues' by Rudolf Beer and Agnes Arber | [August 1918] |
| NLB/56/855 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to Messrs [William Henry] Lang, FRS | 17 June 1919 |
| RR/43/90 | Referee's report by Frederick Orpen Bower, on a paper 'On the spines, sporangia, and spores of Psilophyton princeps, Dawson, shown in specimens from Gaspé' by William Henry Lang | July 1931 |
| NLB/68/72 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Professor [William Henry] Lang, FRS | 8 May 1925 |
| NLB/56/616 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to Professor [William Henry] Lang, FRS | 28 March 1919 |
| RR/38/76 | Referee's report by William Henry Lang, on a paper 'On the structures and affinities of Ankyropteris corrugata' by H S Holden | August 1929 |
| RR/14/60 | Referee's report by Harry Marshall Ward, on a paper 'On apogamy and the development of sporangia upon fern prothalli' by William Henry Lang | 7 March 1898 |
| RR/14/59 | Referee's report by Dukinfield Henry Scott, on a paper 'On apogamy and the development of sporangia upon fern prothalli' by William Henry Lang | 4 March 1898 |
| RR/14/61 | Second referee's report by Dukinfield Henry Scott, on a paper 'On apogamy and the development of sporangia upon fern prothalli' by William Henry Lang | 8 March 1898 |
| NLB/61/637 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Professor [William Henry] Lang, FRS | 29 September 1921 |
| RR/49/9 | Referee's report by William Henry Lang, on a paper 'On the origin and character of xylem rays in gymnosperms' by M W Bannan | [May 1933] |
| NLB/57/107 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to Professor VH [Vernon Herbert] Blackman, FRS, Chairman, Botany Committee | 24 July 1919 |
| RR/58/45 | Referee's report by Hugh Hamshaw Thomas, on a paper 'On the plant-remains from the downtonian of England and Wales' by William Henry Lang | 20 November 1936 |
| RR/58/46 | Referee's report by Albert Charles Seward, on a paper 'On the plant-remains from the downtonian of England and Wales' by William Henry Lang | November 1936 |
| NLB/55/689 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to [Professor William Henry] Lang, FRS | 19 July 1918 |
| RR/68/38 | Referee's report by Hugh Hamshaw Thomas, on a paper 'The lower Devonian flora of the Senni Beds of Monmouthshire and Breconshire' by W N Croft and William Henry Lang | 28 July 1941 |
| RR/68/480 | Referee's report by William Henry Lang, on a paper 'A revision of Williamsoniella' by Thomas Maxwell Harris | [1944] |
| NLB/67/769 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Professor [William Henry] Lang, FRS | 3 March 1925 |
| RR/36/71 | Referee's report by William Henry Lang, on a paper 'The Dictyoxylon cortex of lycopodiales as a constituent of coal' by Clarence A Seyler | [November 1927] |
| NLB/68/336 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Professor [William Henry] Lang, FRS | 22 June 1925 |
| NLB/70/796 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Professor [Frederick Orpen] Bower, FRS | 26 September 1927 |
| RR/19/120 | Referee's report by William Henry Lang, on a paper 'A petrified Williamsonia from Scotland' by Albert Charles Seward | [July 1912] |
| RR/37/68 | Referee's report by William Henry Lang, on a paper 'Schizopodium Davidi gen. et sp. nov. — a new type of stem from devonian rocks of Australia' by Thomas Maxwell Harris | November 1928 |
| RR/19/136 | Referee's report by William Henry Lang, on a paper 'On the comparative anatomy and affinities of the Araucarineae' by Robert Boyd Thomson | [October 1912] |
| RR/29/48 | Referee's report by William Henry Lang, on a paper 'On Tmesipteris Vieillardi, Dangeard, an erect terrestrial species from new caledonia' by Birbal Sahni | November 1923 |
| RR/46/106 | Referee's report by William Henry Lang, on a paper 'A Persian Sigillaria' by Albert Charles Seward | [March 1932] |
| RR/62/82 | Referee's report by William Henry Lang, on a paper 'On the factors that influence external form of fossil plants; with descriptions of the foliage of some species of the Palaeozoic Equisetalean Genus Annularia Sternberg' by John Walton | [January 1936] |
| RR/41/141 | Referee's report by Albert Charles Seward, on a paper 'Some fossil plants of early Devonian type from the Walhalla series, Victoria, Australia' by William Henry Lang and Isabella C Cookson | July 1930 |
| RR/41/142 | Referee's report by Dukinfield Henry Scott, on a paper 'Some fossil plants of early Devonian type from the Walhalla series, Victoria, Australia' by William Henry Lang and Isabella C Cookson | 25 June 1930 |
| RR/43/89 | Referee's report by Dukinfield Henry Scott, on a paper 'On the spines, sporangia, and spores of Psilophyton princeps, Dawson, shown in specimens from Gaspé' by William Henry Lang | 22 July 1931 |
| RR/47/123 | Referee's report by William Henry Lang, on a paper 'On some pteridospermous plants from the Mesozoic rocks of South Africa' by Hugh Hamshaw Thomas | August 1932 |
| RR/51/4 | Referee's report by Albert Charles Seward, on a paper 'On a flora, including vascular land plants, associated with Monograptus, in rocks of Silurian age, from Victoria, Australia' by William Henry Lang and Isabel C Cookson | [July 1934] |
| RR/51/5 | Referee's report by Frederick Ernest Weiss, on a paper 'On a flora, including vascular land plants, associated with Monograptus, in rocks of Silurian age, from Victoria, Australia' by William Henry Lang and Isabel C Cookson | [August 1934] |