Traditional texts
Sutras
The Heart of the Perfection of Wisdom Sutra (pdf)
The Golden Light Sutra (pdf)
Sanghata Sutra (pdf), see also the special website
Benefits of the Sanghata Sutra - by Lama Zopa Rinpoche (pdf)
Vajra Cutter Sutra (pdf)
Benefits of the Vajra Cutter Sutra - by Lama Zopa Rinpoche (pdf)
Texts from the Tibetan tradition
The Three Principles of the Path by Lama Tsong Khapa (1357-1419) & Commentary by H.E. Zong Rinpoche