Swedish is one that rarely uses it to indicate possessive, when the noun already ends in s, x, or z (Lukas' bok), but this is optional. It's used in German and Danish when the noun ends in an s-sound, to prevent ambiguity; using an apostrophe for the possessive is otherwise incorrect.
Nouns in possessive form are often considered to be in Genitive case. The Swedish possessive ending -s is considered to be more of a clitic now.
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https://en.wikipedia.org/wiki/Swedish_grammar#Genitive https://www.duolingo.com/skill/sv/Possessives https://en.wikipedia.org/wiki/Clitic
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I can online, but I can't figure out how to on the app. Thank you though