Hari, what are the figures from those sources? Note that I said "purged", not "executed", and here are some supporting sources:
"[The execution of Tukhachevskii and his immediate associates] marked the beginning of all general purge of the army that was to eliminate 3 of the 5 marshals, 14 of the 16 army commanders, and approximately half of the 70 to 80,000 men in the entire officer corps. Needless to say, this purge necessarily had an extremely deleterious effect on the effectiveness of the Red Army's military leadership." http://mars.acnet.wnec.edu/~grempel/courses/ww2/lectures/purge.html
"More than half the Russian officer corps, some 35,000 experienced men, were executed or banished." http://www.marxists.org/glossary/people/t/u.htm
"All told, 30,000 members of the armed forces were executed. This included fifty per cent of all army officers." http://www.spartacus.schoolnet.co.uk/RUSpurge.htm
[Voice of Russia says] "More than 40,000 army and naval officers were arrested on charges of plotting to betray the Soviet Union to Japan and Germany. The purge effectively denuded the army ranks all way down to the battalion and company level." http://www.vor.ru/century/1937.html
[Even a Marxist-Leninist site says: ] "In the magazine "Young Guard" (1989 -- #9) there was published a document taken from the archives of the Ministry of Defense of the USSR, which was presented at that time to Stalin, Molotov, Voroshilov and Beria on May 5, 1940, that in 1937-1939, 36,898 commanders were dismissed from the ranks of Red Army. More than 75% of them were retired because of their age, sickness, moral grounds (drunkenness) and unworthy of service in the Red Army. From August of 1938, there was working a commission which was told to look into these cases and make recommendations. More than 30,000 requests were received by those dismissed to look into their appeals. In January 1, 1940, this commission returned to their posts more than 12,461 commanders, from those 10,700 were formerly dismissed for political reasons and now put back into ranks." http://www.mltranslations.org/Russia/aucpb.htm
Except, of course, those prevented from "appealing" by a bullet in the head.
regards,
Grant.