References from the California Lichen Catalog
- SIGAL, L. L. 1975.
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Lichens and mosses of California serpentine.
M. A. thesis, San Francisco State University, San Francisco.
- SIGAL, L. L. 1989.
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The lichens of serpentine rocks and soils in California.
Mycotaxon 34: 221–238.
Complete references section