Copyright Act, 1957
Except as otherwise hereinafter provided, copyright shall subsist in any literary, dramatic, musical or artistic work *** published within the lifetime of the author until [sixty years] from the beginning of the calendar year next following the year in which the author dies. Explanation.—In this section the reference to the author shall, in the case of a work of joint authorship, be construed as a reference to the author who dies last.