diff --git a/inst/CITATION b/inst/CITATION
index 570a2a2..8681f56 100644
--- a/inst/CITATION
+++ b/inst/CITATION
@@ -34,5 +34,5 @@ bibentry(bibtype = "article",
   journal = "Journal of Machine Learning Research",
   volume = 12,
   pages = "1977--1981",
-  url = "http://jmlr.csail.mit.edu/papers/v12/hahsler11a.html"
-  )
\ No newline at end of file
+  url = "https://jmlr.csail.mit.edu/papers/v12/hahsler11a.html"
+  )
diff --git a/man/Adult.Rd b/man/Adult.Rd
index 49e26eb..d0b5532 100644
--- a/man/Adult.Rd
+++ b/man/Adult.Rd
@@ -16,7 +16,7 @@ data("AdultUCI")
 }
 \details{
   The \dQuote{Adult} database was extracted from the census bureau database
-  found at \url{http://www.census.gov/} in 1994 by
+  found at \url{https://www.census.gov/} in 1994 by
   Ronny Kohavi and Barry Becker, Data Mining and Visualization, Silicon
   Graphics. It was originally used to predict whether income exceeds USD 50K/yr
   based on census data. We added the attribute \code{income} with levels
@@ -103,7 +103,7 @@ data("AdultUCI")
   }
 }
 \source{
-  \url{http://www.ics.uci.edu/~mlearn/MLRepository.html}
+  \url{https://www.ics.uci.edu/~mlearn/MLRepository.html}
 }
 \references{
   A. Asuncion \& D. J. Newman (2007):
diff --git a/man/Mushroom.Rd b/man/Mushroom.Rd
index 88211f5..1c28fe2 100644
--- a/man/Mushroom.Rd
+++ b/man/Mushroom.Rd
@@ -23,7 +23,7 @@ Object of class \code{transactions}.
 \source{
   The data 
   set was obtained from the UCI Machine Learning Repository at
-  \url{http://archive.ics.uci.edu/ml/datasets/Mushroom}.
+  \url{https://archive.ics.uci.edu/ml/datasets/Mushroom}.
 }
 \references{
 Alfred A. Knopf (1981). Mushroom records drawn from The Audubon Society Field Guide to North American Mushrooms. G. H. Lincoff (Pres.), New York.
diff --git a/man/interestMeasure.Rd b/man/interestMeasure.Rd
index 0ffb84f..cfeb988 100644
--- a/man/interestMeasure.Rd
+++ b/man/interestMeasure.Rd
@@ -7,7 +7,7 @@
 Provides the generic function \code{interestMeasure} and the needed S4 method 
 to calculate various additional interest measures for existing sets of
 itemsets or rules. A searchable list of definitions, equations and references for all available interest measures can be found here: 
-\href{http://michael.hahsler.net/research/association_rules/measures.html}{A Probabilistic Comparison of Commonly Used Interest Measures for Association Rules} (Hahsler, 2015).
+\href{https://michael.hahsler.net/research/association_rules/measures.html}{A Probabilistic Comparison of Commonly Used Interest Measures for Association Rules} (Hahsler, 2015).
 }
 \usage{
 interestMeasure(x, measure, transactions = NULL, reuse = TRUE, ...)
@@ -489,7 +489,7 @@ indices used in population genetics. It evaluates the deviation
 }
 \references{
 Hahsler, Michael (2015). 
-A Probabilistic Comparison of Commonly Used Interest Measures for Association Rules, 2015, URL: \url{http://michael.hahsler.net/research/association_rules/measures.html}.
+A Probabilistic Comparison of Commonly Used Interest Measures for Association Rules, 2015, URL: \url{https://michael.hahsler.net/research/association_rules/measures.html}.
 
 Agrawal, R., H Mannila, R Srikant, H Toivonen, AI Verkamo (1996).
 Fast Discovery of Association Rules.
diff --git a/man/pmml.Rd b/man/pmml.Rd
index a7eabb7..b9a1c02 100644
--- a/man/pmml.Rd
+++ b/man/pmml.Rd
@@ -19,7 +19,7 @@ read.PMML(file)
 Write delegates to package pmml.
 }
 \references{
-  PMML home page: \url{http://dmg.org}
+  PMML 4.4 - Association Rules. \url{http://dmg.org/pmml/v4-4/AssociationRules.html}
 }
 \seealso{
   \code{\link[pmml]{pmml}}.