Sacrae Liturgiae Praxis juxta Ritum Romanum by Jean Baptiste de Herdt, censor of the Roman Sacred Liturgy Academy. In ninth edition (1894), de Herdt gives the following options for the celebration of the Passion (III, 27)
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The celebrant, when unaided by other ministers, is able to sing the Passion with two others. Here he references a decree from the Sacred Congregation of Rites (S.R.C.) from 10 January 1852 (n. 5166, 2 [1]). According to de Herdt, these two others need to be at least minor clerics, that is tonsured, who would be vested in surplice.
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