Note 2 - Summary of Significant Accounting Policies (Tables)

3 Months Ended

Sep. 30, 2021

Notes Tables

Schedules of Concentration of Risk, by Risk Factor [Table Text Block]

	For the Three Months Ended				For the Three Months Ended
	September 30, 2021				September 30, 2020
	Revenue				Revenue
Fund
USO	$	3,142,607	56	%	$	4,893,532	69	%
BNO		519,919	9	%		758,726	11	%
UNG		427,786	8	%		551,554	8	%
USCI		475,584	8	%		250,264	4	%
All Others		1,091,131	19	%		582,225	8	%
Total	$	5,657,027	100	%	$	7,036,301	100	%

	As of September 30, 2021				As of June 30, 2021
	Accounts Receivable				Accounts Receivable
Fund
USO	$	967,323	55	%	$	1,156,691	57	%
BNO		155,325	9	%		196,713	10	%
UNG		146,829	8	%		130,543	6	%
USCI		152,976	9	%		141,346	7	%
All Others		339,377	19	%		412,761	20	%
Total	$	1,761,830	100	%	$	2,038,054	100	%

Property, Plant and Equipment, Estimated Useful Life [Table Text Block]

Category	Estimated Useful Life (in years)
Building		39
Plant and equipment:		5 to 10
Furniture and office equipment		3 to 5
Vehicles		3 to 5