Trade Accounts Payable (Tables)

12 Months Ended

Dec. 31, 2018

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Summary of Trade Accounts Payable

As of December 31, this item includes:

	2017		2018
Invoices payable		1,250,586		591,619
Unbilled services received		132,514		378,670
Notes payable		69,946		109,242
		1,453,046		1,079,531