/usr/share/doc/ruby-gsl/examples/integration/ is in ruby-gsl 2.1.0.3+dfsg1-1build1.
This file is owned by root:root, with mode 0o755.
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/usr/share/doc/ruby-gsl/examples/integration/ahmed.rb
/usr/share/doc/ruby-gsl/examples/integration/cosmology.rb
/usr/share/doc/ruby-gsl/examples/integration/friedmann.gp
/usr/share/doc/ruby-gsl/examples/integration/friedmann.rb
/usr/share/doc/ruby-gsl/examples/integration/gamma-zeta.rb
/usr/share/doc/ruby-gsl/examples/integration/integration.rb
/usr/share/doc/ruby-gsl/examples/integration/qag.rb
/usr/share/doc/ruby-gsl/examples/integration/qag2.rb
/usr/share/doc/ruby-gsl/examples/integration/qag3.rb
/usr/share/doc/ruby-gsl/examples/integration/qagi.rb
/usr/share/doc/ruby-gsl/examples/integration/qagi2.rb
/usr/share/doc/ruby-gsl/examples/integration/qagiu.rb
/usr/share/doc/ruby-gsl/examples/integration/qagp.rb
/usr/share/doc/ruby-gsl/examples/integration/qags.rb
/usr/share/doc/ruby-gsl/examples/integration/qawc.rb
/usr/share/doc/ruby-gsl/examples/integration/qawf.rb
/usr/share/doc/ruby-gsl/examples/integration/qawo.rb
/usr/share/doc/ruby-gsl/examples/integration/qaws.rb
/usr/share/doc/ruby-gsl/examples/integration/qng.rb