How to Make a Strongly Connected Digraph Two-Connected.

András Frank Tibor Jordán How to Make a Strongly Connected Digraph Two-Connected. 414-425 1995 conf/ipco/1995 IPCO db/conf/ipco/ipco1995.html#FrankJ95 http://dx.doi.org/10.1007/3-540-59408-6_69