Alexander Carmichael's Carmina Gadelica: Prayers, blessings and invocations collected by the Scottish folklorist Alexander Carmichael in the Western Isles in the 19th century.
Celtic Monasticism: History and Spirituality: Survey, with pictures, explanations, virtual tours, and links.
How the Irish Were Saved: Issue of Christian History focuses on the conversion of Ireland, and Celtic Christianity from the fifth to the eighth century. Short popularizing articles.