See de Ricci, English book collectors, pp. 52-3; W. Y. Fletcher, English book collectors, pp. 219-21
Manuscripts from Askew's collection of can often be recognised by his characteristic binding, in diced polished calf, with a gilt roll tool of alternating palmettes and fleurs-de-lis motifs:
The collection was sold by G. Leigh & J. Sotheby, London, 7 March, 1785. Those with bindings as above are described as 'corio russico' in the 1785 sale catalogue. Lots 1-312 are printed books, and the manuscripts are arranged by language and material:
| Language | Material | Lots |
| English | Paper | 313-321 |
| Vellum | 322-331 | |
| Latin | Paper | 332-420 |
| Vellum | 421-539 | |
| Greek | Paper | 540-608 |
| Vellum | 609-633 |
A considerable number of the manuscripts are from the collection of Mario Maffei (not just only described as 'olim Maffeianus' in the catalogue).
Manuscripts whose present whereabout are known include: