Possessive proper nouns are formed exactly the same as common possessive nouns. Singular possessive nouns are formed by adding an apostrophe s ('s) to the end of a noun. Plural possessive nouns that end in -s, are formed by adding an apostrophe after the existing -s; for irregular plural nouns that don't end with -s, the possessive is formed by adding the apostrophe s the same as a singular noun.
Examples:
Abraham Lincoln - Abraham Lincoln's Gettysburg Address
Chicago - Chicago's mayor
The Eiffel Tower - The Eiffel Tower's history
Examples of possessives showing ownership by one person:
The plural form of the noun property is properties.
The plural possessive form is properties'.
example: The properties' owners came to an agreement over rights of way.
The possessive form for the noun property is property's.
Example: The property's price is too high for that area.
The plural form of the noun 'property' is properties.The plural possessive form is properties'.Example:All of the properties' owners have been compensated for the damage.
Property's (singular possessive form) rhymes with properties (plural form).
The possessive form of the plural noun managers is managers'.Example: The managers' salaries are not much higher than ours.
Coaster's is singular possessive. The plural is coasters, the plural possessive is coasters'.
The correct form is "its" for the possessive form in the plural. "Its" is used for both the singular and plural possessive forms, without an apostrophe.
The plural is briefs. The plural possessive is briefs'.
The plural is lads. The plural possessive is lads'.
The plural is trollies. The plural possessive is trollies'.
The plural is stations. The plural possessive is stations'.
The plural is relatives. The plural possessive is relatives'.
Museum is singular. Museum's is singular possessive. Museums is plural. Museums' is plural possessive.
The singular possessive form is heart's; the plural possessive form is hearts'.