Trying to understand the footnotes in the documents of the Vatican II council PREFACE:

I am trying to familiarize myself more with more proper catholic doctrines declared by the Vatican II council for when I interact with Catholics, more than just reading the Catechism. A monumental task that I am slown down by the somewhat cryptic footnotes.

EXAMPLE:

cf. St. Augustine, "De Catechizandis Rudibus," C.IV 8: PL. 40, 316. | the very first footnote of the very first constitution listed here, Deī Werbum.

It is fairly easy to understand: confer to "De Catechizandis Rudibus," by St. Augustine of Hippo circa IV... However, I can find nothing for Pl.

What source am I supposed to use? The only compy of the document I can find is not arranged in any such chapters or verses that this could mean, I have no idea. And the only usage of PL. I am acquanted with and can find is plural.

What is 4 8: plural 40, 316?

THESE ARE SOME OTHER EXAMPLES:

f. Council of Trent, session IV, loc. cit.: Denzinger 783 (1501).

What is Denzinger 783?



I can list far more examples, but it just looks very disorganised. I assume it is a very traditional way of doing it and there is nothing wrong with that, I am just both unfamiliar with this format and have no idea where they would want anyone else to look for these citations. This is meant to be the clear, dogmatic statement that 
can be checked back and back again to confirm what the all the council has decided on and what the catholic Church should hold in common, so  I know it is not un-understandable.
"Denzinger" is the Enchiridion Symbolorum et Definitionum, the Handbook of Creeds and Definitions, first compiled by Heinrich Denzinger in the 19th century. This is a summary of sources for the most basic beliefs and creeds of the Church. Unfortunately the most recent version, the 43rd edition published in 2012, is not available online.

Similarly, PL is an abbreviation for Migne's Patrologia Latina, which could be translated The Writings of the Latin Fathers, a collection of (at least in invention) all the major and most of the minor works of Church Fathers, theologians, and other Church scholars writing in Latin through the first millennium or so of Church history.

The abbreviated forms of these names are used in the expectation that most people who have studied Church history will be familiar with the works and by extension with the abbreviations.

Looking at the specific examples you give, I would interpret them:


  cf. [that is, compare] St Augustine, De Catechizandis Rudis [On Pagans to be Catechized], Chapter IV Section 8: [found in] Patrologia Latina Volume 40 page 316.


And


  Council of Trent, session IV, in the place cited, [found in] Denzinger's Enchiridion, point 783 (1501 in the original  numbering)