@techreport{petersen+:nil-tr, 
 author = {Leaf Petersen and Perry Cheng and Robert Harper and Chris Stone},
 title = {Implementing the {TILT} Internal Language}, 
 institution = {School of Computer Science, Carnegie Mellon University}, 
 month = {December}, 
 year = 2000, 
 number = {CMU-CS-00-180},
}