Quotes:Heart Sutra
Zirkoff, Boris
*Book of Sin-King, or The Heart Sutra; also Prajnaparamita Hridaya Sutra. One of the smallest and, with the Diamond Sutra, the most popular of the many Scriptures contained in the vast Prajnaparamita literature. Known in Japan as Shingyo. See D. Suzuki, Manual of Zen Buddhism (with Chinese text), 1935; and Dr. Edward Conze, Buddhist Wisdom Books (with Commentary), 1958.
Source: Boris de Zirkoff, «H. P. Blavatsky Collected Writings», vol. 3, p. 498