The sources I used for this series of expositions are:

(1) The Pulpit Commentary edited by Rev H.D.M.Spence and Rev Joseph Exell. (1907)
(2) The Biblical Illustrator by Rev Joseph Exell.
(3) Paul for Everyone by Tom Wright
(4) 1 Corinthians in the Tyndale New Testament Commentaries by Leon Morris
(5) 1 Corinthians - The People's Bible Commentary by Jerome Murphy-O'Connor.
(6) The Message of 1 Corinthians by David Prior in the Bible Speaks Today series.
(7) Letters to Corinthians by William Barclay in the Daily Study Bible series.

William Barclay sets out very clearly the sequence of letters to the Corinthians:

(1) The Previous Letter, which may be contained in 2Cor6v14 to 7v1.
(2) The arrival of Chloe's people with a letter from the Corinthian Church to Paul.
(3) 1 Corinthians is written in reply and despatched with Timothy.
(4) The situation grows worse and Paul visits Corinth without success. His failure distresses him greatly.
(5) As a result Paul writes The Severe Letter which may be contained in 2Cor10 to 13 and was despatched with Titus.
(6) Anxious for an answer, Paul sets out to meet Titus. In Macedonia he learns all is well and, probably from Philippi, writes 2Cor1 to 9 - The Letter of Reconciliation.