; (B) to form, join, or assist a labor organization or to refrain from any such activity; (C) to bargain collectively through representatives of their own choosing; and (D) to engage in other concerted activities for the purpose of collective bargaining or other mutual aid (including the filing of joint class or collective legal claims) or protection. (2) A requirement for public employers to— (A) recognize the labor organization of its public employees (freely chosen in an election by a majority of such employees voting in the appropriate unit or chosen by voluntary recognition if that method is permitted under State law), without requiring an election to recertify a labor organization that is already recognized as the representative of such employees, unless not less than 30 percent of such employees in the appropriate unit freely sign a petition to decertify such labor organization— (i) not earlier than the date that is 1 year after the date of the election (or after a voluntary recognition if permitted under State law) of the representative; (ii) if a valid collective bargaining agreement covering such employees and labor organization expires, not earlier than the date that is 1 year after the expiration of such agreement; and (iii) not during the term of a valid collective bargaining agreement covering such employees and labor organization, except for the 30-day period beginning on the date that is 90 days before the expiration of such agreement; (B) collectively bargain with such recognized labor organization