For Silvia - Possessive patterns

https://agendaweb.org/grammar/apostrophe-genitive-case.html

https://www.wallstreetenglish.com/blog/english-possessives-the-saxon-genitive/

https://open.books4languages.com/english-b1-grammar/chapter/possessive-case-with-double-genitive/

https://ell.stackexchange.com/questions/148605/using-the-saxon-genitive-or-not

https://forum.wordreference.com/threads/omitting-the-saxon-genitive.2883414/

https://www.bbc.co.uk/worldservice/learningenglish/grammar/learnit/learnitv20.shtml