Incorporation of a high performance, four-cylinder, four-stroke motorcycle engine into a snowmobile application, Gregory A. Davis, Nick S. Dahlheimer, David A. Meyer, Aaron S. Messenger, James R. Johnson, Bernhard P. Bettig
Michigan Tech Publications

Adaptation of four-stroke motorcycle engine to continuously variable transmission for snowmobile application, Brian D. Barr, David J. McKinstry, Aaron S. Messenger, Jason M. Seidenstucker, Daniel H. Kallio, Daniel P. Hoffman, Bernhard P. Bettig
Michigan Tech Publications

Design and testing of a single cylinder, turbocharged, four-stroke snowmobile with E.F.I. and catalytic exhaust treatment, Joseph A. Wegleitner, Scott Miers, Ryan D. Hayes, Scott P. Heim, Dan P. Hoffman, Bernhard P. Bettig
Michigan Tech Publications