Adam Clarke on Ruth 4:20

Amminadab begat Nahshon - The Targum adds, "And Nahshon was chief of the house of his father in the tribe of Judah."

Nahshon begat Salmon - In the Hebrew it is שלמה Salmah, which Houbigant thinks was an error of an ancient scribe, before any final letters were acknowledged in the Hebrew alphabet: for then the word would be written שלמון Salmon, which a scribe, after final letters were admitted, might mistake for שלמה Salmah, and so write it, instead of שלמון Salmon, the ו vau and final nun in conjunction (ון) bearing some resemblance to ה.

The Targum calls him "Salmah the Just; he was the Salmah of Beth-lehem and Netopha, whose sons abolished the watches which Jeroboam set over the highways; and their works and the works of their father were good in Netopha."