9 Those who reside outside Rome, in whatever part of the world they may live,must pay two visits at prescribed intervals to three churches to be appointed by you, Venerable Brethren, your Vicars or Officials, on your or their command, by those who have the charge of souls; or three visits if there are only two churches, or six visits if there is only one; and also must comply with all the conditions already laid down above. This indulgence may be applied by way of suffrage to the souls who have departed this life joined in charity with God. We give you power to reduce the number of the visits according to your judgment to certain churches in the case of chapters, congregations, as well secular as regular, communities, confraternities, universities, and colleges where the visits are made in procession.
Source: Quod Auctoritate (Vatican.va)