I find very helpful the book
Reformed Confessions Harmonized
A harmony of 7 Church documents in a systematic way.
It is so practical to have the confessions and catechisms
side by side in columns, and arranged by doctrine
It includes:
the Belgic Confession of Faith (1561),
the Heidelberg Catechism (1563),
the Canons of Dort (1618-19).
Second Helvetic Confession (1566).
the Westminster Confession of Faith (1646-47)
Larger and Shorter Westminster Catechisms (1647).
Title : Reformed Confessions Harmonized
Paperback: 304 pages
Publisher: Baker Books (August 1, 1999)
ISBN-10: 080105222X
Editors
Joel R. Beeke (Reformed Church)
Sinclair B. Ferguson (Presbyterian Church)
It is also a blessing to see such a fruitful cooperation between brothers
in Christ from a Reformed and Presbyterian background
you can also take a look inside