Spanish and other Iberian languages do not make a distinction between a journal and a magazine. They use the same word for both, a revista. For translators this can cause us a headache if information about a particular publication is sparse. An abstract I was translating today mentioned two underground Catalan revistas from the 1940s, so it was hard to check whether they were journals or magazines.
One solution is to do what I did twice in the previous paragraph: translate revista with its hypernym, the more generic word publication. But if we want to be more precise – you probably don’t want to repeat the word publication too often in the same text – then you can ask the author, who will probably know about the publication and will be able to tell you which is the more appropriate word.
But the author might not understand the difference between the two terms, or might think that magazine refers only to glossy, tabloid-like magazines like Hello!, when in fact some magazines, like Time, are more serious. To solve this problem, this slide presentation in Spanish is a good resource to send your author, who should be able to identify which word is more appropriate based on the explanations on the slides.
This nuance between a journal and a magazine is another example of the dangers of machine translation. Google Translate might pick the right word if your sentence contains the name of a well-known magazine like ¡Hola! (the Spanish version of Hello!), but for a 1940s publication it will most likely just be guessing.