The late Reuben J. Swanson is best known for his New Testament Greek Manuscripts series in which variant readings are arranged in horizontal lines against Codex Vaticanus. His books, including that on Galatians, are now available from SBL in addition to Eisenbrauns.
Reuben J. Swanson, ed. New Testament Greek Manuscripts: Galatians. Variant Readings Arranged in Horizontal Lines Against Codex Vaticanus. William Carey International University Press, 2000. 0865850690, 9780865850699.