As for sources, here is what Cawley's Medieval Lands has to say on his birth and death and the sources the information came from:
CHARLES, son of PEPIN "le Bref" King of the Franks & his wife Bertrada [Berta] "au Grand Pied" ([near Aix-la-Chapelle[57]] 2 Apr [747/48]-Aix-la-Chapelle 28 Jan 814, bur Aix-la-Chapelle, Chapelle Sainte-Marie). He is named first son of King Pépin and Bertrada in the Cartulaire of Saint-Bertin[58]. A calendar from Lorsch records the birth “IV Non Apr” of “Karoli imperatoris et semper augusti”[59]. The year of his birth is open to debate. The Annales Fuldenses record his death in 814 at the age of about 71[60], which would suggest [742/43] which is inconsistent with the suggested marriage date of his parents (see above). The Annalium Petavianorum Continuatio record the birth in 747 of “Karolus rex”[61]. Settipani suggests that this date should be considered “Old Style”. This assumes (1) that the Lorsch calendar correctly records the day of his birth, (2) that the order of entries for that year in the Annalium Petavianorum Continuatio is chronological (the preceding sentence records Carloman’s departure for Rome which is dated to after 15 Aug 747[62]), and (3) that 2 Apr 747 was Easter Sunday which he suggests would have been noted in sources if it had been the emperor’s date of birth[63]. It seems preferable to indicate [747/48] as Charles’s possible date of birth. The conjectures about Charles’s place of birth were discussed at length by Hahn in the mid-19th century[64] ... The necrology of Prüm records the death "814 V Kal Feb" of "Karolus imperator"[69]. The Annales Fuldenses record the death "814 V Kal Feb" of "Karolus imperator" at Aachen at the age of about 71[70]. The necrology of Saint-Germain-des-Prés records the death 814 “V Kal Feb” of “domni Karoli imperatoris”[71].
The footnotes are as follows:
[57] Settipani (1993), p. 191.
[58] Saint-Bertin, p. 56.
[59] Mabillon, J. (1704) Annales Ordinis S. Benedicti, Tome II (Paris), p. 116.
[60] Annales Fuldenses 814 MGH SS I, p. 356.
[61] Annalium Petavianorum Continuatio, 747, MGH SS I, p. 11.
[62] Halkin, J. & Roland, C. G. (1909) Recueil des chartes de l’abbaye de Stavelot-Malmédy (Brussels), 18, p. 51 [not yet consulted].
[63] Settipani (1993), p. 192, footnote 3 continued from previous page.
[64] Hahn, M. ‘Sur le lieu de naissance de Charlemagne’, Mémoires Couronnés et autres mémoires publiés par l’Académie Royale des Sciences, des lettres et des beaux-art de Belgique, Tome XI (Brussels, 1861).
[69] Annales Necrologici Prumienses, MGH SS XIII, p. 219.
[70] Annales Fuldenses 814 MGH SS I, p. 356.
[71] Longnon ‘Obituaire de l’abbaye de Saint-Germain des Prés’, p. 23.
I think by European Aristocrats Project guidelines, a box for Medieval Lands should go at the bottom of the profile.