Here a few comments on the translation of Augustine's work De Bono Coniugali -- On the Good of Marriage -- published by Oxford University Press. Overall, it is probably the best translation of the whole work currently in print, though a much older (and harder to read) translation is freely available online: On the Good of Marriage at New Advent; this new translation is available from Amazon: De Bono Coniugali, De Sancta Virginitate (Oxford Early Christian Texts); unfortunately it is expensive, seemingly being priced more for academic libraries than individuals. A more affordable modern translation is in Marriage and Virginity (Works of Saint Augustine: A Translation for the 21st Century) translated by Ray Kearney.
There are a few erroneous or difficult to understand translations in the work.
Chapter 11: "The fact is that intercourse necessary for begetting children carries no blame, and it alone is proper to marriage. But the intercourse which goes beyond this necessity is no longer subject to reason, but to lust. However, intrinsic to the character of marriage is the refusal to demand it oneself, but also a willingness to grant itto one's spouse, so that he may not sin mortally through fornication."
A more accurate, and easier to understand translation would be: "The
intercourse that is necessary for begetting children carries no blame,
and it alone is properly marital intercourse. But intercourse that goes
beyond this necessity is no longer obedient to reason but to lust.
Nevertheless it is also a married person's duty, not indeed to demand
such intercourse, but to grant it to one's spouse, so that he may not
sin mortally through fornication.
Chapter 32: "Though procreation is the sole purpose of marriage,
even if this does not ensue and is the only reason why it [marriage]
takesplace, the nuptial bond is loosed only by the death of a spouse." Here the word marriage should be inserted for clarity.
Summary Outline of On the Good of Marriage (De bono conjugali) by St. Augustine.
Summary Outline of Familiaris Consortio by Pope John Paul II
Summary Outline of Casti Connubii by Pope Pius XI (1930) - Also the history of various events concerning divorce and contraception that lead up to the encyclical.