Gospel Principles Chapter 14: Priesthood Organization
"What is a Quorum?" by Elder L. Tom Perry (Quorum of the 12 Apostles)- One of the greatest blessings is belonging to a quorum.
"A Priesthood Quorum" by President Henry B. Eyring (1st Presidency but Elder of the 12 at the time)- The strength of a quorum comes from its members.
Here are articles, talks, and Q & A's about the specific quorums of the Priesthood even though they aren't all by Apostles, they are by General Authorities and are helpful if you have a specific question about that particular organization.
Deacon Quorum- Q & A with the Presiding Bishopric.
Teachers Quorum- Same in the series with the Presiding Bishopric.
Priests Quorum- Again with the Presiding Bishopric.
Elders Quorum- Fourth in the series by Elder Dale E. Miller of the Seventy.
High Priests Quorum- Same series this time by Elder David E. Sorensen of the Presidency of the Seventy.
The Presiding Bishopric- by Bishop Keith B. McMullin (2nd Counselor in the Presiding Bishopric)
Quorums of the Seventy- by Elder Earl C. Tingy (Presidency of the 70)
The Twelve Apostles- Same series this time by President Boyd K. Packer (of the 12)
Quorum of the First Presidency- Last in the series by President Gordon B. Hinckley (Prophet and President at the time)