Ah, the Annals. Really the starting point for figuring out Pepin and Charles, when working from the primary sources. Punchy, pithy, and without (much) guile, the Annals are a readable, and even enjoyable, year-by-year chronicle of the doings of the great and the good and the not so good in the Frankish kingdom.
The Annals begin in 741, with, “Charles, mayor of the palace, died,” and that’s it. Which is perhaps the soul of brevity. However there are two versions of the Annals: the original, terser version, and the one called “Revised” by the scholars. The Revised version for 741 goes on to include news about Charles’ three sons, and the beginnings of a fantastic family drama, worthy of Tolstoy, that played out over the next few years. The translations I’ve seen show the original version, and then any emendations by “the Revisor.” The multiple authors of the Annals are unknown, but putting forth candidates and shooting them down seems to be great sport in academia.