1) A 9-channel integrated time-to-digital converter with sub-nanosecond resolution
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=666065&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D666065
2) A flexible multi-channel high-resolution time-to-digital converter ASIC
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=949889&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D949889
3) A CMOS Time-to-Digital Converter LSI with Half-Nanosecond Resolution Using a Ring Gate Delay Line