Trass, H 1968: Indeks samblikuruhmituste kasutamiseks ohu saastatuse maaramisel. [An index for the utilization of lichen groups to determine air pollution.]. - Eesti Loodus11: 628. [RLL List # 71 / Rec.# 18919] Keywords: ESTONIA/ AIR POLLUTION/ USSR/ POPULAR
Abstract: 1 tab. [In Estonian; English abstract included on an unnumbered page in the table of contents.]