_______(1) Gross margin is a non-GAAP financial measure and is discussed under Targa Resources Partners ??? Non-GAAP Financial Measures.(2) Operating margin is a non-GAAP financial margin and is discussed under Targa Resources Partners ??? Non-GAAP Financial Measures.(3) Adjusted EBITDA is net income before interest, income taxes, depreciation and amortization, gains or losses on debt repurcha