Article history: Received 12 September 2015 Accepted 21 December 2015 Available online xxxx Submitted by R. Brualdi MSC: primary 05E15 secondary 15A21

Article history: Received 15 April 2014 Accepted 5 May 2014 Available online 29 May 2014 Submitted by R. Brualdi MSC: 05C20 05C50 15A18

Article history: Received 15 January 2013 Accepted 5 February 2014 Available online xxxx Submitted by R. Brualdi MSC: 05C72 05C57 68R10 94A99

Article history: Received 28 July 2013 Accepted 30 August 2013 Available online xxxx Submitted by R. Brualdi MSC: 15A18 15A69 65F15 65F10

Article history: Received 24 September 2009 Accepted 6 November 2009 Available online 20 February 2010 Submitted by R. Bhatia AMS classification: 15B48 15B36 91A40 91B66

Article history: Received 11 December 2012 Received in revised form 15 June 2014 Accepted 8 July 2014 Available online 17 July 2014 Communicated by R. Gavaldà

Article history: Received 1 March 2009 Received in revised form 20 November 2009 Accepted 6 April 2010 Available online 11 April 2010 Responsible Editor: R. Molva

Article history: Received 21 December 2009 Received in revised form 26 July 2010 Accepted 30 August 2010 Available online 6 September 2010 Communicated by R. Wu

Article history: Received 25 November 2013 Accepted 31 January 2014 Available online 26 February 2014 Submitted by R. Brualdi MSC: 15A15 15B99 41A05

Article history: First received on December 17, 2014 and was under review for 1 month Available online 26 February 2015 Replication Editor: Donald R. Lehmann