Reference / Source: This narration is in Ibn Sa'd's "al-Tabaqat al-Kubra" (3/515 and 516) in separate parts, as a statement of Muhammad bin 'Umar al-Waqidi himself.

Details of the narration: Among the imams who counted him (this Companion) among those who took part in the Battle of Badr are 'Urwah bin al-Zubayr (see: al-Tabarani's "al-Mu'jam al-Kabir", no. 6502), Ibn Shihab al-Zuhri (see: Ibn Abi 'Asim's "al-Ahad wa al-Mathani", no. 1824, and al-Tabarani as well, no. 6503), and Ibn Ishaq (see: Ibn Hisham's "al-Sirah al-Nabawiyyah" 1/695).

Important point: It is established from Anas bin Malik (may Allah be pleased with him) in Khalifah bin Khayyat's "Tarikh" (p. 111) that: Abu Dujanah (may Allah be pleased with him) threw himself (on the day of al-Yamamah) into "Hadiqat al-Mawt" (the Garden of Death), whereupon his leg was broken, but he kept fighting until he was martyred.

Details of the narration: Abu Dujanah's participation in the killing of Musaylimah the Liar was alluded to by Wahshi bin Harb (may Allah be pleased with him) in his hadith in which he related the killing of Hamzah (may Allah be pleased with him) on the day of Uhud and then the story of al-Yamamah. Wahshi said: "Then when the affair of Musaylimah happened and the army set out, I set out with it and took that same spear (harbah) of mine. When we met, I and a man from the Ansar rushed at him... and your Lord knows best which of us killed him."
Research note: Ibn 'Abd al-Barr stated with certainty in "al-Isti'ab" (p. 798) that he took part in the killing of Musaylimah. Ibn al-Jawzi said in "al-Muntazam" (4/82): "There is no doubt that the Ansari was Abu Dujanah Simak bin Kharashah," and Ibn Kathir also affirmed this with certainty in "al-Bidayah wa al-Nihayah" (5/364).
Reference / Source: This hadith of Wahshi was narrated by al-Tayalisi (no. 1410) and Ibn Ishaq (via Ibn Hisham 2/70-72). Its chain in al-Tayalisi is "sahih", and by way of Ibn Ishaq it is "hasan".