1. Ahrendt, L.W.A., 1961. Berberis and Mahonia: A taxonomic revision. Botanical Journal of the Linnean Society, 57(369), pp.1-410. https://doi.org/10.1111/j.1095-8339.1961.tb00889.x
2. Anon., 1858. Obituary Notices. John Forbes Royle. Proceedings of the Linnean Society, 70, pp.31-37.
3. Chandra, S., 1984. Himalayan Explorers & Collectors, 1. John Forbes Royle 1799-1858. Himalayan Research & Development, 3, pp.70-74.
4. Gage, A.T. and Stearn, W.T., 1988. A Bicentenary History of the Linnean Society of London. Academic Press, London.
5. Harrison, S., 1978. Recent work on the herbarium of John Forbes Royle (1799-1858) at Merseyside County Museum (LIV.). Taxon, 27(1), pp.21-33. https://doi.org/10.2307/1220474
6. Hooker, J.D., 1875. Flora of British India, Vol. 1. L. Reeve & Co., London.
7. Hooker, J.D. and Thomson, T., 1855. Flora Indica. W. Pamplin, London.
8. Linnean Society, 1863. A Catalogue of a portion of the natural history collections of the Linnean Society of London Sold by order of the Council and confirmed by a General Meeting of the Society, consisting of shells, birds, insects, horns, herbariums from all parts of the world, and a variety of other natural history specimens which will be sold by Auction by Mr. J.C. Stevens at his Great Rooms, 38, King Street, Covent Garden, on Tuesday 10th November, 1863, at half-past twelve o’clock precisely. Alfred Robbins, Printer, London.
9. Rao, R.R., Hussain, T., Dutt, B. and Garg, A., 1998. Revision of the Family Berberidaceae of Indian Region-II. Rheedea, 8(2).
10. Royle, J.F., 1833-1840. Illustrations of the Botany and Other Branches of the Natural History of the Himalayan Mountains, 11 parts. Wm. Allen & Co., London.
11. Royle, J.F., 1837. On the Lycium of Dioscorides. Trans. Linn. Soc Lond., 17(1).
12. Stansfield, H., 1953a. The Royle Herbarium. A classic collection of plants from N.W. India and the Himalaya. The North Western Naturalist, 24, pp.250-265.
13. Stansfield, H., 1953b. The Roylean Herbarium. The Pharmaceutical Journal, 170, pp.74-79.
14. Stansfield, H., 1953c. Type specimens from the Himalaya. Museums Journal, pp.262-295.
15. Stansfield, H., 1954. Plant Collecting in the Himalayas. The discovery of a classic collection of plants from North Western Himalayas – (1823-1831). Liverpool Libraries, Museums & Arts Committee Bulletin, 3(3), pp.4-38.
16. Stearn, W.T., 1943. Royle’s “Illustrations of the Botany of the Himalayan Mountains”. Journal of Arnold Arboretum, 24(4), pp.484-487. https://doi.org/10.5962/p.185487