MathSciNet bibliographic data MR1900698 11F72 Gamburd, Alex On the spectral gap for infinite index "congruence'' subgroups of ${\rm SL}_2(\bold Z)$${\rm SL}_2(\bold Z)$. Israel J. Math. 127 (2002), 157–200. Article

For users without a MathSciNet license , Relay Station allows linking from MR numbers in online mathematical literature directly to electronic journals and original articles. Subscribers receive the added value of full MathSciNet reviews.