In addition to his research work, he is well known for his books on algorithms and formal languages coauthored with Jeffrey Ullman and Alfred Aho, regarded as classic texts in the field.
Osim istraživačkog rada, poznat je i po svojim knjigama o algoritmima i formalnim jezicima, koautoriranih sa Jeffreyjem Ullmanom, a koje se u samoj struci smatraju klasicima.