CONSOLIDATED BALANCE SHEETS (Parentheticals) - USD ($)	Jun. 30, 2021	Jun. 30, 2020
Allowance for doubtful accounts on trade receivables (in dollars)	$ 14,948	$ 13,171
Common stock, par value (in dollars per share)	$ 1	$ 1
Prior Cumulative Preferred Stock
Preferred stock, par value (in dollars per share)	$ 5	$ 5
Prior Cumulative Preferred Stock - Series A
Preferred stock, liquidation preference (in dollars)	$ 2,400,000	$ 2,370,000
Prior Cumulative Preferred Stock - Series B
Preferred stock, liquidation preference (in dollars)	$ 2,355,000	$ 2,325,000
Convertible Cumulative Preferred
Preferred stock, par value (in dollars per share)	$ 20	$ 20
Cumulative Preferred Stock - Series A
Preferred stock, liquidation preference (in dollars)	$ 5,370,395	$ 5,311,862
Cumulative Preferred Stock - Series B
Preferred stock, liquidation preference (in dollars)	$ 875,211	$ 865,672