Greg Spence recently toured the US and was in Texas Sept 7-17, 2015. He has really helped me play and teach trumpet and brass instruments better. He presented at the ITG The International Trumpet Guild in Huntsville, Baylor University, West Texas AM, UNT.
Greg is the author of Mystery to Mastery and has many videos online. They are excellent. I encourage your to watch his videos and read his materials.
Click this link for more information. http://mysterytomastery.com/articles/?art=34
Search YouTube for Greg Spence.