US5696673; US5706408; US5721677; US5773840; US5786602; US5793647; US5811825;
US5811827; US5825017; US5828566; US5844668; US5854491; US5854880; US5866915;
US5917726; US5940302; US5981965; US6044183; US6108072; US6127689; US6138055;
US6148898; US6211506; US6317953; US6415191; US6419003; US6466305; US6617601;
US6618155; US6825936; US7420196; US7525114; US7936464; US8786836; US9476707;
US9927372B2; CA2309008; CA2355757; CA2536411; CA2599472; CA2738012; EP2076733;
EP2486392; EP2920581; ES2400380; GB2076733; GB2507813; FR2076733; DE2076733;
IT2076733; FI119259; FI124263; FI124299; FI125408B; CN101529200B; CN102575985B;
JP51553