How exactly do these kinds of compound words work?
"Okun's Law" and "Philips Curve" rather than "Okun Law" and "Philips' Curve"?
Is there any grammar book I can look for?
How exactly do these kinds of compound words work?
"Okun's Law" and "Philips Curve" rather than "Okun Law" and "Philips' Curve"?
Is there any grammar book I can look for?
There is no rule, different writers choose different styles. Without moving from my desk I can find the following examples of references to the same thing:
and then the same all over again but calling it a theorem rather than a rule.
If the proper name is not in a possessive form, then sometimes the definite article is used, as in "The Bayes Rule" but even that is not standardised.