To the bibliography for "semi-direct" sources of Vulgar Latin given on pg. 504 add Hanciaux 1989-95 (Hanciaux, René. 1989-95. Graphies latines vulgaires et variantes orthographiques tirees des manuscrits. Mons: Atelier Offset de l'Université de l'Etat à Mons.) This work of which seven volumes have appeared to date is an alphabetical listing of "incorrect" spellings found in the manuscripts of various classical and late antique authors. It is all very undigested, but valuable if one is trying to find examples. For example, the spelling calligat 'is dark' for cālīgat
is attested in ms. H of Aetna 312. Ms. Helmstadtiensis 332 dates from the 15th century, but the geminate l spelling is not worthless since we know that calligo for cālīgō was stigmatized in the Appendix Probi and some Romance forms, e.g. Nuor. gaḍḍíndzu ‘the staggers’—a form of mad cow disease—continue the geminate l.