diff --git a/metadata/entries/Frequency_Moments.toml b/metadata/entries/Frequency_Moments.toml
--- a/metadata/entries/Frequency_Moments.toml
+++ b/metadata/entries/Frequency_Moments.toml
@@ -1,44 +1,45 @@
 title = "Formalization of Randomized Approximation Algorithms for Frequency Moments"
 date = 2022-04-08
 topics = [
   "Computer science/Algorithms/Approximation",
   "Mathematics/Probability theory",
 ]
 abstract = """
 In 1999 Alon et. al. introduced the still active research topic of
 approximating the frequency moments of a data stream using randomized
 algorithms with minimal space usage. This includes the problem of
 estimating the cardinality of the stream elements - the zeroth
 frequency moment. But, also higher-order frequency moments that
 provide information about the skew of the data stream. (The
 <i>k</i>-th frequency moment of a data stream is the sum
 of the <i>k</i>-th powers of the occurrence counts of each
 element in the stream.) This entry formalizes three randomized
 algorithms for the approximation of
 <i>F<sub>0</sub></i>,
 <i>F<sub>2</sub></i> and
 <i>F<sub>k</sub></i> for <i>k ≥
 3</i> based on [<a
 href=\"https://doi.org/10.1006/jcss.1997.1545\">1</a>,
 <a
 href=\"https://doi.org/10.1007/3-540-45726-7_1\">2</a>]
 and verifies their expected accuracy, success probability and space
 usage."""
 license = "bsd"
 note = ""
 
 [authors]
 
 [authors.karayel]
 homepage = "karayel_homepage"
 
 [contributors]
 
 [notify]
 karayel = "karayel_email"
 
 [history]
 
 [extra]
 
 [related]
+dois = ["10.4230/LIPIcs.ITP.2022.21"]