Reference

From 1984 to 1991, he was active as a teacher in Ala and Võhma. From 1991 to 1994, Aab worked in Finland. Upon returning to Estonia, Aab started working in ...

From 1984 to 1991, he was active as a teacher in Ala and Võhma. From 1991 to 1994, Aab worked in Finland. Back in Estonia, Aab became involved ...

The modern industrial use of oil shale for oil extraction dates to the mid-19th century and started growing just before World War I.