Nadir, I found one: Catechism of the Council of Trent, TAN Books edition, p. 318. It's a little harsh, but I believe it's consistent with the mind of the Church (the pre-Vatican II Church, of course. What the modern Catholic Church says is completely immaterial, since they are not really the Catholic Church). Of course, the call is from holy God, but the clergy are responsible for implementing that call.