Nicolas Barré was a prolific spiritual writer and correspondent. His "Oeuvres complètes" (in French) containing the founding documents of the Institute, other important texts and numerous letters to people for whom he was a spiritual director, is available online. You can find any text or any word found in these texts by using the comprehensive index.
"Oeuvres Complètes" is a very useful resource for anyone doing research into spirituality, religious and apostolic life in seventeenth century France as well as exploring the origins of these subjects today.
The texts are available in English by request via 'Get in Touch'.