This form of the disease is rare.

VOA: special.2009.01.06

"My hope is this is not going to be a rare situation;

VOA: standard.2010.02.09

This is clear that this was a mistake,". He added that incidents such as this one are rare, especially after the United States imposed new restrictions on air strikes in an effort to avoid civilian casualties.

VOA: standard.2009.11.07