It was given to me by a Greek Drupla (soon to be Lama) friend of mine who probably got it during one of her two three year retreats at Dhagpo Kundreul Ling in France (thus explaining why the text is in French). I will ask her about the source the next time I talk to her.
Oh, by the way dzoki, since a tsog is a Vajrayana/tantric practice you will probably (definitely?) need a lung to do the specific practice.
"Meditation is familiarisation with realisation"
Jigten Sumgon Gonchig: The Single Intent, the Sacred Dharma
"Oh great bodhisattva, you ought to understand the quintessence in this way: Whatever appears is one in its suchness. It cannot be falsified by anyone. The sovereign of unconceptualised sameness dwells in the spirit of the Dharmakaya which cannot be cognised."
The All Creating Sovereign, Mind of Perfect Purity.
"Ego is constantly attempting to acquire and apply the teachings of spirituality for its own benefit."