If you are referring to non-canonical gospels and epistles, such as the Protoevangelium of James, Gospel of Thomas, letter of Clement etc. their position is the same as that of the Catholic Church, since they accept the Catholic Canon of the New Testament. These do not constitute divine revelation. If you are speaking of the writings of the Fathers of the Church and the proceedings of early Church councils, that varies with denomination, individual ministers and the seminaries in which they were trained, since Protestants reject all authority outside of Sacred Scripture (including Sacred Tradition, from which scripture derives, and the authority of the Church to establish the canon of scripture. illogical but true)