Arya, S. R., S. Bhagat, Virendra Singh, and Ombir Singh. 1990. “Spade Planting-an Economical and Faster Planting Technique of Silver Fir and Spruce in Western Himalayas”. Indian Forester 116 (8):618-21. https://doi.org/10.36808/if/1990/v116i8/8885.