British Museum | Museum of Modern Art | Bremen | Metropolitan Museum of Art | American Museum of Natural History | Victoria and Albert Museum | Natural History Museum | San Francisco Museum of Modern Art | Honolulu Museum of Art | museum | Whitney Museum of American Art | Museum of Fine Arts, Boston | Los Angeles County Museum of Art | Solomon R. Guggenheim Museum | National Air and Space Museum | Brooklyn Museum | National Baseball Hall of Fame and Museum | Hermitage Museum | National Museum of Racing and Hall of Fame | Museum of Contemporary Art | Field Museum of Natural History | Philadelphia Museum of Art | Imperial War Museum | Smithsonian American Art Museum | National Museum | National Museum of Natural History | Museum of Fine Arts, Houston | Denver Art Museum | Cleveland Museum of Art | Museum of Contemporary Art, Los Angeles |
Beginning in 1904 he worked as a zoological assistant at the Städtischen Museum für Natur-, Völker- und Handelskunde (Municipal Museum of natural history, ethnology and trade history) in Bremen, under the direction of Hugo Schauinsland (1857-1937).
While being stars in Mexico, they have been touring Europe for the last several years, especially Germany, where their European Label Übersee Records is located.