Death Date of Librada Perez Muñoz

I am a bit perplexed by the search engines, I have tried different spellings and I can see the mothers last name is not used until recently, such that the grave of Lamberto (her husband) only says "de Alba" no mention his mother, Jimenes. Lamberto died in Aguascalientes, so it would natural to think that she died in the same city.

Any leads would be greatly appreciate,

Abraham de Alba Avila
(son of Jorge, grandson of Pedro, greatgrandson of Lamberto)