https://torontodawah.com/is-the-salah-invalid-for-the-one-praying-alone-behind-the-first-or-second-line-lajnah-permanent-committee-for-scholarly-research-and-ifta-shaykh-muhammad-nasiruddin-al-albani-shaykh-muh/
Is The Salah Invalid For The One Praying Alone Behind The First Or Second Line - Lajnah (Permanent Committee For Scholarly Research And Ifta’), Shaykh Muhammad Nasiruddin Al-Albani, Shaykh Muhammad Ibn Ibraheem Aala Al-Shaykh, And Shaykh Ibn Uthaymeen