1972, Kenneth A. Mueller, Teaching Total Percussion, Move only the arms when playing from one timpano to the other.
1984, Percussion Anthology: A Compendium of Percussion Articles from the Instrumentalist, In most cases, when one timpano is used, numerous gliss effects are required (or no special pedaling at all).
1990, w:Kent Kennan; w:Donald Grantham, The Technique of Orchestration, As in string writing, the indication is a line between the notes (both of which must be within the range of one timpano, of course).
2013, ErtuÄŸrul Sevsay, The Cambridge Guide to Orchestration, Usually two or more timpani are used together, except for a few rare cases in pre-Classical music where only one timpano is required.
