The Canons of the Church of England THE DOCTRINE OF THE CHURCH OF ENGLAND
Canon A5 and the wording of Section 5(1) of the Worship and Doctrine Measure 1974
The doctrine of the Church of England is grounded in the Holy Scriptures, and in such teachings of the ancient Fathers and Councils of the Church as are agreeable to the said Scriptures.
In particular such doctrine is to be found in the Thirty-nine Articles of Religion, the Book of Common Prayer, and the Ordinal.
CANON C15 OF THE DECLARATION OF ASSENT
1(1) The Declaration of Assent to be made under this Canon shall be in the form set out below:
PREFACE
The Church of England is part of the One, Holy, Catholic and Apostolic Church worshipping the one true God, Father, Son and Holy Spirit. It professes the faith uniquely revealed in the Holy Scriptures and set forth in the catholic creeds, which faith the Church is called upon to proclaim afresh in each generation. Led by the Holy Spirit, it has borne witness to Christian truth in its historic formularies, the Thirty-nine Articles of Religion, the Book of Common Prayer and the Ordering of Bishops, Priests and Deacons. In the declaration you are about to make will you affirm your loyalty to this inheritance of faith as your inspiration and guidance under God in bringing the grace and truth of Christ to this generation and making Him known to those in your care?
DECLARATION OF ASSENT
I A B, do so affirm, and accordingly declare my belief in the faith which is revealed in the Holy Scriptures and set forth in the catholic creeds and to which the historic formularies of the Church of England bear witness; and in public prayer and administration of the sacraments, I will use only the forms of service which are authorised or allowed by Canon.
Packer's little book does a pretty good job of giving the historical and contemporary background behind them, even if you don't agree with his conclusion. But of course, this only applies to the CoE. I'm not sure how many churches in the communion require subscription to the Articles besides them. I know the TEC does not.