@techreport{plt-tr2009-drscheme-v4.2.1, author = {Robert Bruce Findler and PLT}, title = {{DrScheme}: {PLT} Programming Environment}, number = {PLT-TR2009-drscheme-v4.2.1}, type = {Reference Manual}, institution = {PLT Scheme Inc.}, month = {July}, year = {2009}, url = {http://download.plt-scheme.org/doc/4.2.1/pdf/drscheme.pdf}, note = {\url{http://plt-scheme.org/techreports/}} }