Synonym for "the end of" [closed]

Basically, I wanted to paraphrase the following sentence :

These subjects have been profoundly studied since the end of 1950’s.

What could I use instead of the bold part? Please make light on me. Thanks!

... since the end of the 1950s.

... since the late 1950s.

... since late in the 1950s.

... post 1959.

... since 1960.

Suppose the issues began to be studied extensively because of some event, such as the publication of a book about them, cited as J.Smith, 1959.

... post publication of J.Smith, 1959.

... since the publication of J.Smith, 1959.

... since the stir caused by the publication of J.Smith, 1959.

... since fashions changed post publication of J.Smith, 1959.