Lichens :
an illustrated guide to the British and Irish species /
by Frank S. Dobson.

APA Citation

Dobson, F. (Frank S.). (1992). Lichens: an illustrated guide to the British and Irish species. 3rd enl. ed. Slough, England: Richmond.

MLA Citation

Dobson, Frank (Frank S.). Lichens: an Illustrated Guide to the British And Irish Species. 3rd enl. ed. Slough, England: Richmond, 1992.

Warning: These citations may not always be complete (especially for serials).