Can. 135

Clerici, in maioribus ordinibus constituti, exceptis iis de quibus in can. 213, 214, tenentur obligatione quotidie horas canonicas integre recitandi secundum proprios et probatos liturgicos libros.

Cited in the encyclopedia

Clergy, Clerics
Deacon and Archdeacon
Divine Office (Officium Ecclesiasticum; Hours; Canonical Hours; Liturgy of the Hours; Opus Dei; Opus Divinum; Divine Office)