The Gita is a small but significant part of the Upanishads which itself is a small part of the larger work of the Vedas. The Patanjali Sutras are probably the best overview since Patanjali himself is credited with innovating Yoga. I love Paramahansa Yogananda too - but he was considered a maverick outsider to the more established Vedanta community.
Though for me this gives him more credibility since his point of view originates more from insight and inspiration than pedantics.