Story : The Next Housing Shock - As more and more Americans face mortgage foreclosure, banks' crucial ownership documents for the properties are often unclear and are sometimes even bogus - a condition that's causing lawsuits and hampering an already weak housing market. Scott Pelley reports. Robert Anderson and Daniel Ruetenik are the producers. Gospel for Teens - Lesley Stahl spends a year following the inspirational leader of a gospel music program for teenagers in Harlem and her students as they learn to sing this original American art form and build the confidence and character it inspires. Shari Finkelstein is the producer. THIS IS A DOUBLE-LENGTH SEGMENT.