Index: doc/bibliography/pl.bib
===================================================================
--- doc/bibliography/pl.bib	(revision 247c8f3768259b1d898a1b667c1c05d222066aad)
+++ doc/bibliography/pl.bib	(revision d438111c9a21e364ddbdd5277ae5652b3c5cc5d5)
@@ -2499,4 +2499,25 @@
     pages	= {325-361},
 }
+
+@article{Tarjan75,
+ keywords = {union-find},
+ contributer = {a3moss@uwaterloo.ca},
+ author = {Tarjan, Robert Endre},
+ title = {Efficiency of a Good But Not Linear Set Union Algorithm},
+ journal = {J. ACM},
+ issue_date = {April 1975},
+ volume = {22},
+ number = {2},
+ month = apr,
+ year = {1975},
+ issn = {0004-5411},
+ pages = {215--225},
+ numpages = {11},
+ url = {http://doi.acm.org/10.1145/321879.321884},
+ doi = {10.1145/321879.321884},
+ acmid = {321884},
+ publisher = {ACM},
+ address = {New York, NY, USA},
+} 
 
 @book{Eiffel,