I would like to ask if any specific rules apply to the usage of some and some of phrases and especially in which cases either of them is not suitable for a sentence.
I understand that e.g. a phrase like some of my friends is grammatically correct, but what makes me hesitate is the following sentence from the field of physics:
Some of relevant ideas were mentioned many years ago.
Can the of preposition be used in this case, or is the sentence incorrect?
(As a side note, I think that the word mentioned is not chosen very well and should be replaced by a more suitable verb or a construction saying that there have been scientists who stated important theorems such as the divisibility of atoms.)