Heffernan and Shelton refer to Phil. 1.21-23; 1 Cor 9:15; 2 Cor 6.9; and Col 2.20. Heffernan, Thomas J.; James E. Shelton «Paradisus in carcere: The Vocabulary of Imprisonment and the Theology of Martyrdom in the Passio Sanctarum Perpetuae et Felicitas». Journal of Early Christian Studies, 14, 2, 2006, pàg. 217–23. DOI: 10.1353/earl.2006.0035.