Update green-paper.tex

See #42, release log:

• 86fa6ee by @yegor256: Merge pull request #43 from va...
• 97bfcb3 by @yegor256: Merge pull request #42 from si...
• 969f7e2 by @vassilevsky: Remove duplicate paragraph
• ec60d0c by @silverbonegg: Update green-paper.tex
• c565a87 by @yegor256: reword
• 6edb71e by @yegor256: name

Released by Rultor 1.67.4, see build log