1.1. In English Dictionaries and Encyclopedias

• apostle | Merriam-Webster’s collegiate dictionary. (Eleventh ed.)

1.2. In Bible Dictionaries and Encyclopedias

• Apostle, Apostleship. | Baker Encyclopedia of the Bible
• Authority, Human | Dictionary of Biblical Imagery
• Apostle | Dictionary of Jesus and the Gospels
• Apostle, Apostleship | Dictionary of the later New Testament and its developments
• Apostle | Dictionary of Paul and his letters
• Apostle | Easton’s Bible Dictionary
• ἀπόστολος, ου, ὁ | Exegetical Dictionary of the New Testament
• Apostle | Harper’s Bible Dictionary
• Apostle | The New Bible Dictionary (3rd Edition)
• Apostle | New Dictionary of Theology
• Apostle | Nelson’s New Illustrated Bible Dictionary
• apostle | Nelson’s New Christian Dictionary
• Apostle | Smith’s Bible Dictionary

1.3. In Theological Dictionaries and Encyclopedias

• ἀπόστολος | The Theological Dictionary of the New Testament

1.4. In Theological Journals

• Culver , Robert Duncan. Apostles And The Apostolate In The New Testament. BSac 134:534 (Apr 77) p. 132-44
• Lawson, Steven J. The Priority of Biblical Preaching: An Expository Study of Acts 2:42-47: The Primacy of the Apostles’ Teaching. BSac 158:630 (Apr 01) p. 201-17
• Macleod, David J. The Year of Public Favor, Part 4: The Twelve Apostles (Matthew 10:1–4; Mark 3:13–19; Luke 6:12–16). EmJ 13:1 (Summer 2004) p. 8-61
• Kent, Homer A., Jr.A Time To Teach: Teaching Was Basic in the Practice of the Apostles. GTJ 1:1 (Spr 1980) p. 12-14

2.1. In Systematic Theologies

• Packer, J. I. Apostles. Concise theology: A guide to historic Christian beliefs. Wheaton, Ill.: Tyndale House.
• Grenz, S., Guretzki, D., & Nordling, C. F. apostle, apostolicity.. Pocket dictionary of theological terms. Downers Grove, Ill.: InterVarsity Press. 14
• Ferguson, S. B., & Packer, J. Apostle. New dictionary of theology (electronic ed.). Downers Grove, IL: InterVarsity Press. 41

2.2. In Other Books

1.1. In English Dictionaries and Encyclopedias

• apostle | Merriam-Webster’s collegiate dictionary. (Eleventh ed.)
• apostle | Concise Oxford English Dictionary

1.2. In Bible Dictionaries and Encyclopedias

• Apostle, Apostleship. | Baker Encyclopedia of the Bible
• Authority, Human | Dictionary of Biblical Imagery
• Apostle | Dictionary of Jesus and the Gospels
• Apostle, Apostleship | Dictionary of the later New Testament and its developments
• Apostle | Dictionary of Paul and his letters
• Apostle | Easton’s Bible Dictionary
• ἀπόστολος, ου, ὁ | Exegetical Dictionary of the New Testament
• Apostle | Harper’s Bible Dictionary
• Apostle | The New Bible Dictionary (3rd Edition)
• Apostle | New Dictionary of Theology
• Apostle | Nelson’s New Illustrated Bible Dictionary
• apostle | Nelson’s New Christian Dictionary
• Apostle | Smith’s Bible Dictionary
• Apostle | Anchor Yale Bible Dictionary
• ἀπόστολος | Moulton – Milligan

1.3. In Theological Dictionaries and Encyclopedias

• ἀπόστολος | The Theological Dictionary of the New Testament
• ἀπόστολος | Spicq Theological Lexicon of the New Testament

1.4. In Theological Journals

• Culver , Robert Duncan. Apostles And The Apostolate In The New Testament. BSac 134:534 (Apr 77) p. 132-44
• Lawson, Steven J. The Priority of Biblical Preaching: An Expository Study of Acts 2:42-47: The Primacy of the Apostles’ Teaching. BSac 158:630 (Apr 01) p. 201-17
• Macleod, David J. The Year of Public Favor, Part 4: The Twelve Apostles (Matthew 10:1–4; Mark 3:13–19; Luke 6:12–16). EmJ 13:1 (Summer 2004) p. 8-61
• Kent, Homer A., Jr.A Time To Teach: Teaching Was Basic in the Practice of the Apostles. GTJ 1:1 (Spr 1980) p. 12-14

2.1. In Systematic Theologies

• Packer, J. I. Apostles. Concise theology: A guide to historic Christian beliefs. Wheaton, Ill.: Tyndale House.
• Grenz, S., Guretzki, D., & Nordling, C. F. apostle, apostolicity.. Pocket dictionary of theological terms. Downers Grove, Ill.: InterVarsity Press. 14
• Ferguson, S. B., & Packer, J. Apostle. New dictionary of theology (electronic ed.). Downers Grove, IL: InterVarsity Press. 41

2.2. In Other Books