Reference / Source: (2) It was narrated by Ibn Sa'd in "al-Tabaqat" (10/ 82) and al-Tabari in his "Tarikh" (11/ 603) via Muhammad bin Umar al-Waqidi, with this chain.
Technical note / Defect ('illah): The narrator Ibn Abi Sabrah in the chain is "muttaham" (accused of lying).

Reference / Source: It was narrated by Ibn Sa'd (10/ 206) from al-Waqidi, from Muhammad bin Abd Allah, from al-Zuhri; and (by another chain) from al-Waqidi, from Kathir bin Zayd, from al-Muttalib bin Abd Allah bin Hantab; the two of them mentioned it at length.

Reference / Source: It was narrated by al-Zubayr bin Bakkar in "al-Muntakhab min Kitab Azwaj al-Nabi (peace and blessings be upon him)" (p. 39) from Muhammad bin Hasan, from Muhammad bin Musa Abu Ghaziyyah, from Sa'id bin Abi Zayd, from Rubayh bin Abd al-Rahman bin Abi Sa'id al-Khudri, from his father, from his grandfather, who said: The Messenger of Allah (peace and blessings be upon him) married Hafsah bint Umar in Sha'ban at the start of the thirtieth month after the Hijrah, two months before (the battle of) Uhud.
Grading: This chain is "talif" (ruined, extremely weak) and cannot be relied upon, because in it is Muhammad bin Hasan (Ibn Zabalah), who is "matruk" and "muttaham".

Important point: That the Prophet (peace and blessings be upon him) married Hafsah before Uhud is the view of al-Waqidi and his companion Ibn Sa'd. This marriage took place after the death of her first husband Khunays bin Hudhafah al-Sahmi, who died of wounds he received at Badr. It is also said that he was killed at Uhud, but Ibn Sayyid al-Nas said in "Uyun al-Athar" (2/ 369): The first (view) is better known. See also "Fath al-Bari" (15/ 351).