There are links to them in this article: http://thisismynext.com/2011/08/16/htc-sues-apple-patents/

One article I read suggested "two of which HTC acquired through a $75m purchase of ADC Technologies in April. (The third was homegrown at HTC.)"

US Patent #7,417,944 (ADC) US Patent #7,672,219 (ADC) US Patent #7,765,414 (HTC)