Voluntas has many more books which are the personal property of the magi, than they have available in the covenant library. Recently, the books of Desiderius were added to the covenant's main library though.
In Es De Res Totum (Summa, Quality 9, Creo 14)
Pertingens Oculus Occulta Vitia (Summa, Quality 7, Intellego 12)
Unum Ad Aliud (Summa, Quality 11, Muto 10)
In Interitum Carne (Summa, Quality 5, Perdo 12)
Regendi Quae Procul (Summa, Quality 9, Rego 9)
In Ignitus Carnis Hominis (Summa, Quality 4, Corpus 16)
Iam Vides Me Tibi Non (Summa, Quality 5, Imagonem 14)
(Tractatus, Mentem 7)
(Tractatus, Mentum 8)
(Tractatus, Imagonem 7)
(Tractatus, Vim 6)
(Tractatus, Corpus 9)
(Tractatus, Creo 7)
(Tractatus, Creo 8)
(Tractatus, Intellego 6)
(Tractatus, Rego 7)
(Tractatus, Perdo 5)
(Tractatus, Perdo 8)
(Tractatus, Perdo 7)
(Tractatus, Muto 6)