Archived from the original on 16 February 2003. Retrieved 30 December 2015. ↑ Dirk Schulze-Makuch; David H. Grinspoon; Ousama Abbas; Louis N. Irwin; Mark A. Bullock (March 2004). "A Sulfur-Based Survival Strategy for Putative Phototrophic Life in the Venusian Atmosphere.".