CIC/1917, can. 0534
§ 2. In precibus pro obtinendo consensu ad contrahenda debita vel obligationes, exprimi debent alia debita vel obligationes, quibus ipsa persona moralis, religio vel provincia vel domus, ad eum diem gravatur; secus obtenta venia invalida est."
Sources
1917 Codex Iuris Canonicis, can. 534, in: www.jgray.org (Last access: 29.03.2016).
Codex Iuris Senior, can. 534, in: www.catho.org (Last access: 29.03.2016).
GASPARRI, Pietro (Hg.), Codex Iuris Canonici Pii X Pontificis Maximi iussu digestus, Benedicti Papae XV auctoritate promulgatus, Rom 1917, can. 534, S. 153, in: archive.org (Last access: 29.03.2016).