Modern Hagiography
Lives of the Saints by Alban Butler.
Lives of the Saints by Francis Weninger.
Lives of the Saints by Sabine Baring-Gould.
Anecdotes and Incidents: Ecclesiastical and Religious.
Contemporary Hagiography
Pope Gregory the Great spoke about Saint Servulus in his homily on the Parable of the Sower (Luke 8.4-15). He also wrote about him in his Dialogues.
Art & Architecture
Death of San Servolo by Tommaso Chiari (info here and here)
Guide to Christian Iconography: Images, Symbols, and Texts
Emblems of Saints by Which They Are Distinguished in Works of Art by F. C. Husenbeth.