It sounds like you’re looking for a paper (or information to write one) about the
Instead, the RAE’s etymological information is embedded within its flagship dictionary: the Diccionario de la Lengua Española (DLE). For each entry, the DLE includes a brief etymological note in square brackets [ ] indicating the word’s origin (e.g., Latin, Arabic, Greek, a Germanic language, etc.). diccionario etimologico rae
That said, the most famous and authoritative etymological dictionary for Spanish is (later expanded by José Antonio Pascual). The RAE often relies on Corominas’s work. It sounds like you’re looking for a paper
However, it’s important to clarify a key fact: a Germanic language