Yes, I’d like to have that link. Thanks. Similarly I wonder if you can link to a Church document on the liceity of marital relations after child bearing years have passed. I’ve seen a Jesuit moral theologian cited here who taught that older couples should cease relations and “elevate their thoughts” as they prepared for death. I asked my pastor about that, and his response was that it was perfectly fine for older couples to be intimate. But I still wonder about that as a Jesuit moral theologian’s training and credentials must surely be more in depth than a parish priest’s. Maybe intimacy or the possible need to cease intimacy is part of the “just moderation” teaching?
I’ll have to post the other part later, but first the Encyclicals of Pope Pius XII are here:
papalencyclicals.net/Pius12/index.htm
Note particularly this one to Midwives:
papalencyclicals.net/Pius12/P12midwives.htm
Excerpt
Human dignity in the conjugal act
This explanation of Ours on the functions of your professional apostolate would be incomplete, if We did not add further a few more words about the defense of human dignity in the use of the procreative faculty.
The same Creator, Who in His bounty and wisdom willed to make use of the work of man and woman, by uniting them in matrimony, for the preservation and propagation of the human race, has also decreed that in this function the parties should experience pleasure and happiness of body and spirit. Husband and wife, therefore, by seeking and enjoying this pleasure do no wrong whatever. They accept what the Creator has destined for them.
Nevertheless, here also, husband and wife must know how to keep themselves within the limits of a just moderation. As with the pleasure of food and drink so with the sexual they must not abandon themselves without restraint to the impulses of the senses. The right rule is this: the use of the natural procreative disposition is morally lawful in matrimony only, in the service of and in accordance with the ends of marriage itself. Hence it follows that only in marriage with the observing of this rule is the desire and fruition of this pleasure and of this satisfaction lawful. For the pleasure is subordinate to the law of the action whence it derives, and not vice versa—the action to the law of pleasure. And this law, so very reasonable, concerns not only the substance but also the circumstances of the action, so that, even when the substance of the act remains morally safe, it is possible to sin in the way it is performed.
The transgression of this law is as old as original sin. But in our times there is the risk that one may lose sight of the fundamental principle itself. At present, in fact, it is usual to support in words and in writing (and this by Catholics in certain circles) the necessary autonomy, the proper end, and the proper value of sexuality and of its realization, independently of the purpose of procreating a new life. There is a tendency to subject to a new examination and to a new norm the very order established by God and not to admit any other restraint to the way of satisfying the instinct than by considering the essence of the instinctive act. In addition there would be substituted a license to serve blindly and without restraint the whims and instincts of nature in the place of the moral obligations to dominate passions; and this sooner or later cannot but turn out to be a danger to morals, conscience and human dignity.
If nature had aimed exclusively, or at least in the first place, at a reciprocal gift and possession of the married couple in joy and delight, and if it had ordered that act only to make happy in the highest possible degree their personal experience, and not to stimulate them to the service of life, then the Creator would have adopted another plan in forming and constituting the natural act. Now, instead, all this is subordinated and ordered to that unique, great law of the “generatio et educatio prolis,” namely the accomplishment of the primary end of matrimony as the origin and source of life.
Unfortunately, unceasing waves of hedonism invade the world and threaten to submerge in the swelling tide of thoughts, desires and acts the whole marital life, not without serious dangers and grave prejudice to the primary duty of husband and wife.
Excellent post.
. The marital act is an act of mutual self-giving; it is not a simple exercise of the intellect or will. There are physiological changes occurring during this act which can potentially strengthen the bond between husband and wife. I think the key would be “moderation in all things”. Just as for food, we are not expected either to starve or to be gluttons, a middle way must be found by the couple. 
The book is in four volumes. Click on “Vol. 2” at the top of the page, and scroll down to Chapter 9, “Marriage, Sexual Acts, and Family Life”; there’s quite an in-depth discussion there.