diff --git a/R/alanwood.R b/R/alanwood.R
index ddc77a95..356537ea 100644
--- a/R/alanwood.R
+++ b/R/alanwood.R
@@ -18,7 +18,7 @@
 #' @references Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 #' Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 #' Information from the Web. Journal of Statistical Software, 93(13).
-#' <doi:10.18637/jss.v093.i13>.
+#' \doi{10.18637/jss.v093.i13}.
 #' @export
 #' @examples
 #' \dontrun{
diff --git a/R/chebi.R b/R/chebi.R
index 014bd359..cb76ac2e 100644
--- a/R/chebi.R
+++ b/R/chebi.R
@@ -52,7 +52,7 @@
 #' @references Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 #'   Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 #'   Information from the Web. Journal of Statistical Software, 93(13).
-#'   <doi:10.18637/jss.v093.i13>.
+#'   \doi{10.18637/jss.v093.i13}.
 #' @export
 #' @examples
 #' \donttest{
@@ -225,7 +225,7 @@ get_chebiid <- function(query,
 #' @references Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 #' Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 #' Information from the Web. Journal of Statistical Software, 93(13).
-#' <doi:10.18637/jss.v093.i13>.
+#' \doi{10.18637/jss.v093.i13}.
 #' @export
 #' @examples
 #' \donttest{
diff --git a/R/chemspider.R b/R/chemspider.R
index 40208b18..02d0054a 100644
--- a/R/chemspider.R
+++ b/R/chemspider.R
@@ -164,7 +164,7 @@ cs_control <- function(datasources = vector(),
 #' @references Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 #' Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 #' Information from the Web. Journal of Statistical Software, 93(13).
-#' <doi:10.18637/jss.v093.i13>.
+#' \doi{10.18637/jss.v093.i13}.
 #'
 #' @export
 #' @examples
@@ -336,7 +336,7 @@ get_csid <- function(query,
 #' @references Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 #' Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 #' Information from the Web. Journal of Statistical Software, 93(13).
-#' <doi:10.18637/jss.v093.i13>.
+#' \doi{10.18637/jss.v093.i13}.
 #' @export
 #' @examples
 #' \dontrun{
diff --git a/R/etox.R b/R/etox.R
index 3f284932..e71173a7 100644
--- a/R/etox.R
+++ b/R/etox.R
@@ -25,7 +25,7 @@
 #' @references Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 #' Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 #' Information from the Web. Journal of Statistical Software, 93(13).
-#' <doi:10.18637/jss.v093.i13>.
+#' \doi{10.18637/jss.v093.i13}.
 #' @export
 #' @examples
 #' \dontrun{
@@ -153,7 +153,7 @@ get_etoxid <- function(query,
 #' @references Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 #' Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 #' Information from the Web. Journal of Statistical Software, 93(13).
-#' <doi:10.18637/jss.v093.i13>.
+#' \doi{10.18637/jss.v093.i13}.
 #' @export
 #' @examples
 #' \dontrun{
@@ -278,7 +278,7 @@ etox_basic <- function(id, verbose = TRUE) {
 #' @references Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 #' Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 #' Information from the Web. Journal of Statistical Software, 93(13).
-#' <doi:10.18637/jss.v093.i13>.
+#' \doi{10.18637/jss.v093.i13}.
 #' @export
 #' @examples
 #' \dontrun{
diff --git a/R/extractors.R b/R/extractors.R
index a27f2b19..b58159d0 100644
--- a/R/extractors.R
+++ b/R/extractors.R
@@ -7,7 +7,7 @@
 #' @references Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 #' Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 #' Information from the Web. Journal of Statistical Software, 93(13).
-#' <doi:10.18637/jss.v093.i13>.
+#' \doi{10.18637/jss.v093.i13}.
 #' @export
 cas <- function(x, ...){
   UseMethod("cas")
diff --git a/R/nist.R b/R/nist.R
index 9033bdd1..7f738e05 100644
--- a/R/nist.R
+++ b/R/nist.R
@@ -309,7 +309,7 @@ tidy_ritable <- function(ri_xml) {
 #'   "Retention Indices" in NIST Chemistry WebBook, NIST Standard Reference
 #'   Database Number 69, Eds. P.J. Linstrom and W.G. Mallard,
 #'   National Institute of Standards and Technology, Gaithersburg MD, 20899,
-#'   \url{https://doi.org/10.18434/T4D303}.
+#'   \doi{10.18434/T4D303}.
 #'
 #' @export
 #' @note Copyright for NIST Standard Reference Data is governed by the Standard
diff --git a/R/opsin.R b/R/opsin.R
index b8df6212..e90e0559 100644
--- a/R/opsin.R
+++ b/R/opsin.R
@@ -15,7 +15,7 @@
 #'
 #' @references Lowe, D. M., Corbett, P. T., Murray-Rust, P., & Glen, R. C. (2011).
 #' Chemical Name to Structure: OPSIN, an Open Source Solution. Journal of Chemical Information and Modeling,
-#' 51(3), 739–753. \url{https://doi.org/10.1021/ci100384d}
+#' 51(3), 739–753. \doi{10.1021/ci100384d}
 #' @examples
 #' \donttest{
 #' opsin_query('Cyclopropane')
diff --git a/R/pan.R b/R/pan.R
index 616dc95f..bd8e3513 100644
--- a/R/pan.R
+++ b/R/pan.R
@@ -1,6 +1,6 @@
 #' Query the PAN Pesticide database
 #'
-#' Retrieve information from the PAN database (\url{http://www.pesticideinfo.org/}).
+#' Retrieve information from the PAN database (\url{https://www.pesticideinfo.org/}).
 #' This function is currently broken.
 #' @import xml2
 #' @importFrom utils adist
@@ -13,7 +13,7 @@
 #' @param verbose logical; should a verbose output be printed on the console?
 #' @param ... currently not used.
 #' @return a named list of 73 entries,
-#'   see \url{http://www.pesticideinfo.org/Docs/ref_overview.html} for more information.
+#'   see \url{https://www.pesticideinfo.org/about/overview.html} for more information.
 #'   If \code{match="best"} an additional entry \code{match_score} with the normalized
 #'   Levenshtein distance (0 = perfect match, 1 = worst match).
 #'
@@ -84,7 +84,7 @@ pan_query <- function(query, from = c("name", "cas"),
       if (verbose) webchem_message("na")
       return(NA)
     }
-    baseurl <- 'http://www.pesticideinfo.org/List_Chemicals.jsp?'
+    baseurl <- 'https://www.pesticideinfo.org/List_Chemicals.jsp?'
     baseq <- paste0('ChooseSearchType=Begin&ResultCnt=50&dCAS_No=y&dEPA_PCCode=y&',
                     'dDPR_Chem_Code=y&dUseList=y&dClassList=y&dMol_weight=y&',
                     'dEPA_Reg=y&dCA_Reg=y&dPIC=y&dPOP=y&dWHOObsolete=y&dEPA_HAP=y&',
@@ -141,7 +141,7 @@ pan_query <- function(query, from = c("name", "cas"),
       # return also source url
       # xmlview::xml_view(nd, add_filter = TRUE)
       source_url <- xml_attr(xml_find_all(nd, ".//a[contains(., 'Details')]"), 'href')
-      out[['source_url']] <- paste0('http://www.pesticideinfo.org/', source_url)
+      out[['source_url']] <- paste0('https://www.pesticideinfo.org/', source_url)
 
       ind <-
         matcher(
diff --git a/R/pubchem.R b/R/pubchem.R
index 0d3b43ab..014f8390 100644
--- a/R/pubchem.R
+++ b/R/pubchem.R
@@ -64,7 +64,7 @@
 #' @references Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 #' Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 #' Information from the Web. Journal of Statistical Software, 93(13).
-#' <doi:10.18637/jss.v093.i13>.
+#' \doi{10.18637/jss.v093.i13}.
 #' @note Please respect the Terms and Conditions of the National Library of
 #' Medicine, \url{https://www.nlm.nih.gov/databases/download.html} the data
 #' usage policies of National Center for Biotechnology Information,
@@ -296,7 +296,7 @@ get_cid <-
 #' @references Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 #' Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 #' Information from the Web. Journal of Statistical Software, 93(13).
-#' <doi:10.18637/jss.v093.i13>.
+#' \doi{10.18637/jss.v093.i13}.
 #' @note Please respect the Terms and Conditions of the National Library of
 #' Medicine, \url{https://www.nlm.nih.gov/databases/download.html} the data
 #' usage policies of National Center for Biotechnology Information,
@@ -541,7 +541,7 @@ pc_synonyms <- function(query,
 #' \url{https://pubchem.ncbi.nlm.nih.gov/sources/}.
 #' @references Kim, S., Thiessen, P.A., Cheng, T. et al. PUG-View: programmatic
 #' access to chemical annotations integrated in PubChem. J Cheminform 11, 56
-#' (2019). https://doi.org/10.1186/s13321-019-0375-2.
+#' (2019). \doi{10.1186/s13321-019-0375-2}.
 #' @seealso \code{\link{get_cid}}, \code{\link{pc_prop}}
 #' @examples
 #' # might fail if API is not available
@@ -592,7 +592,7 @@ pc_sect <- function(id,
 #' \url{https://pubchem.ncbi.nlm.nih.gov/classification/#hid=72}.
 #' @references Kim, S., Thiessen, P.A., Cheng, T. et al. PUG-View: programmatic
 #' access to chemical annotations integrated in PubChem. J Cheminform 11, 56
-#' (2019). https://doi.org/10.1186/s13321-019-0375-2.
+#' (2019). \doi{10.1186/s13321-019-0375-2}.
 #' @examples
 #' # might fail if API is not available
 #' \donttest{
@@ -671,7 +671,7 @@ pc_page <- function(id,
 #' be found at \url{https://pubchem.ncbi.nlm.nih.gov/classification/#hid=72}.
 #' @references Kim, S., Thiessen, P.A., Cheng, T. et al. PUG-View: programmatic
 #' access to chemical annotations integrated in PubChem. J Cheminform 11, 56
-#' (2019). https://doi.org/10.1186/s13321-019-0375-2.
+#' (2019). \doi{10.1186/s13321-019-0375-2}.
 #' @examples
 #' # might fail if API is not available
 #' \donttest{
diff --git a/R/utils.R b/R/utils.R
index 79cab42f..a38b88d8 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -21,7 +21,7 @@
 #' @references Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 #' Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 #' Information from the Web. Journal of Statistical Software, 93(13).
-#' <doi:10.18637/jss.v093.i13>.
+#' \doi{10.18637/jss.v093.i13}.
 #' @export
 #' @examples
 #' is.inchikey('BQJCRHHNABKAKU-KBQPJGBKSA-N')
@@ -190,7 +190,7 @@ is.inchikey_format = function(x, verbose = TRUE) {
 #' @references Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 #' Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 #' Information from the Web. Journal of Statistical Software, 93(13).
-#' <doi:10.18637/jss.v093.i13>.
+#' \doi{10.18637/jss.v093.i13}.
 #'
 #' @export
 #' @examples
@@ -336,7 +336,7 @@ extr_num <- function(x) {
 #' @references Grabner, M., Varmuza, K., & Dehmer, M. (2012). RMol:
 #' a toolset for transforming SD/Molfile structure information into R objects.
 #' Source Code for Biology and Medicine, 7, 12.
-#' \url{https://doi.org/10.1186/1751-0473-7-12}
+#' \doi{10.1186/1751-0473-7-12}
 #' @export
 
 parse_mol <- function(string) {
diff --git a/R/wikidata.R b/R/wikidata.R
index 60829ba2..d664bda3 100644
--- a/R/wikidata.R
+++ b/R/wikidata.R
@@ -135,7 +135,7 @@ get_wdid <-
 #' @seealso \code{\link{get_wdid}}
 #'
 #' @references Willighagen, E., 2015. Getting CAS registry numbers out of WikiData. The Winnower.
-#' \url{http://dx.doi.org/10.15200/winn.142867.72538}
+#' \doi{10.15200/winn.142867.72538}
 #'
 #' Mitraka, Elvira, Andra Waagmeester, Sebastian Burgstaller-Muehlbacher, et al. 2015
 #' Wikidata: A Platform for Data Integration and Dissemination for the Life Sciences and beyond. bioRxiv: 031971.
diff --git a/man/aw_query.Rd b/man/aw_query.Rd
index 9446f7f4..8c826bef 100644
--- a/man/aw_query.Rd
+++ b/man/aw_query.Rd
@@ -47,5 +47,5 @@ aw_query("79622-59-6", from = 'cas')
 Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 Information from the Web. Journal of Statistical Software, 93(13).
-<doi:10.18637/jss.v093.i13>.
+\doi{10.18637/jss.v093.i13}.
 }
diff --git a/man/chebi_comp_entity.Rd b/man/chebi_comp_entity.Rd
index db6c0e5e..19791bd4 100644
--- a/man/chebi_comp_entity.Rd
+++ b/man/chebi_comp_entity.Rd
@@ -62,5 +62,5 @@ Hastings J, Owen G, Dekker A, Ennis M, Kale N, Muthukrishnan V,
 Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 Information from the Web. Journal of Statistical Software, 93(13).
-<doi:10.18637/jss.v093.i13>.
+\doi{10.18637/jss.v093.i13}.
 }
diff --git a/man/cs_convert.Rd b/man/cs_convert.Rd
index 790bca28..9f7b8bc6 100644
--- a/man/cs_convert.Rd
+++ b/man/cs_convert.Rd
@@ -64,5 +64,5 @@ cs_convert(160, from = "csid", to = "smiles")
 Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 Information from the Web. Journal of Statistical Software, 93(13).
-<doi:10.18637/jss.v093.i13>.
+\doi{10.18637/jss.v093.i13}.
 }
diff --git a/man/etox_basic.Rd b/man/etox_basic.Rd
index ae705126..26b241c9 100644
--- a/man/etox_basic.Rd
+++ b/man/etox_basic.Rd
@@ -42,7 +42,7 @@ sapply(out, function(y) y$cas)
 Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 Information from the Web. Journal of Statistical Software, 93(13).
-<doi:10.18637/jss.v093.i13>.
+\doi{10.18637/jss.v093.i13}.
 }
 \seealso{
 \code{\link{get_etoxid}} to retrieve ETOX IDs,
diff --git a/man/etox_targets.Rd b/man/etox_targets.Rd
index cf92ed36..5f9618fe 100644
--- a/man/etox_targets.Rd
+++ b/man/etox_targets.Rd
@@ -37,7 +37,7 @@ etox_targets( c("20179", "9051"))
 Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 Information from the Web. Journal of Statistical Software, 93(13).
-<doi:10.18637/jss.v093.i13>.
+\doi{10.18637/jss.v093.i13}.
 }
 \seealso{
 \code{\link{get_etoxid}} to retrieve ETOX IDs,
diff --git a/man/extractors.Rd b/man/extractors.Rd
index 835796d0..38c1a0da 100644
--- a/man/extractors.Rd
+++ b/man/extractors.Rd
@@ -28,5 +28,5 @@ Extract parts from webchem objects
 Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 Information from the Web. Journal of Statistical Software, 93(13).
-<doi:10.18637/jss.v093.i13>.
+\doi{10.18637/jss.v093.i13}.
 }
diff --git a/man/get_chebiid.Rd b/man/get_chebiid.Rd
index b5ced240..1bfbccc0 100644
--- a/man/get_chebiid.Rd
+++ b/man/get_chebiid.Rd
@@ -91,5 +91,5 @@ Hastings J, Owen G, Dekker A, Ennis M, Kale N, Muthukrishnan V,
 Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
   Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
   Information from the Web. Journal of Statistical Software, 93(13).
-  <doi:10.18637/jss.v093.i13>.
+  \doi{10.18637/jss.v093.i13}.
 }
diff --git a/man/get_cid.Rd b/man/get_cid.Rd
index 6ff5ed70..0b729992 100644
--- a/man/get_cid.Rd
+++ b/man/get_cid.Rd
@@ -146,5 +146,5 @@ information in PubChem. Nucleic acids research, gkv396.
 Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 Information from the Web. Journal of Statistical Software, 93(13).
-<doi:10.18637/jss.v093.i13>.
+\doi{10.18637/jss.v093.i13}.
 }
diff --git a/man/get_csid.Rd b/man/get_csid.Rd
index fb0959f7..6ad1190c 100644
--- a/man/get_csid.Rd
+++ b/man/get_csid.Rd
@@ -69,5 +69,5 @@ get_csid("QTBSBXVTEAMEQO-UHFFFAOYAR", from = "inchikey")
 Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 Information from the Web. Journal of Statistical Software, 93(13).
-<doi:10.18637/jss.v093.i13>.
+\doi{10.18637/jss.v093.i13}.
 }
diff --git a/man/get_etoxid.Rd b/man/get_etoxid.Rd
index 0ac3a264..226d40f3 100644
--- a/man/get_etoxid.Rd
+++ b/man/get_etoxid.Rd
@@ -54,7 +54,7 @@ get_etoxid("203-157-5", from = "ec") # Paracetamol
 Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 Information from the Web. Journal of Statistical Software, 93(13).
-<doi:10.18637/jss.v093.i13>.
+\doi{10.18637/jss.v093.i13}.
 }
 \seealso{
 \code{\link{etox_basic}} for basic information,
diff --git a/man/is.cas.Rd b/man/is.cas.Rd
index ed53dc47..8388ee1b 100644
--- a/man/is.cas.Rd
+++ b/man/is.cas.Rd
@@ -39,5 +39,5 @@ is.cas('64-17-6')
 Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 Information from the Web. Journal of Statistical Software, 93(13).
-<doi:10.18637/jss.v093.i13>.
+\doi{10.18637/jss.v093.i13}.
 }
diff --git a/man/is.inchikey.Rd b/man/is.inchikey.Rd
index 2aaf6d5c..3796d367 100644
--- a/man/is.inchikey.Rd
+++ b/man/is.inchikey.Rd
@@ -45,5 +45,5 @@ Chemical Identifier." Journal of Cheminformatics 7.1 (2015): 23.
 Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 Information from the Web. Journal of Statistical Software, 93(13).
-<doi:10.18637/jss.v093.i13>.
+\doi{10.18637/jss.v093.i13}.
 }
diff --git a/man/nist_ri.Rd b/man/nist_ri.Rd
index 9e6f83f5..8400892a 100644
--- a/man/nist_ri.Rd
+++ b/man/nist_ri.Rd
@@ -82,7 +82,7 @@ NIST Mass Spectrometry Data Center, William E. Wallace, director,
   "Retention Indices" in NIST Chemistry WebBook, NIST Standard Reference
   Database Number 69, Eds. P.J. Linstrom and W.G. Mallard,
   National Institute of Standards and Technology, Gaithersburg MD, 20899,
-  \url{https://doi.org/10.18434/T4D303}.
+  \doi{10.18434/T4D303}.
 }
 \seealso{
 \code{\link{is.cas}} \code{\link{as.cas}}
diff --git a/man/opsin_query.Rd b/man/opsin_query.Rd
index cfe7cd76..e5396a1e 100644
--- a/man/opsin_query.Rd
+++ b/man/opsin_query.Rd
@@ -30,5 +30,5 @@ opsin_query(c('Cyclopropane', 'Octane', 'xxxxx'))
 \references{
 Lowe, D. M., Corbett, P. T., Murray-Rust, P., & Glen, R. C. (2011).
 Chemical Name to Structure: OPSIN, an Open Source Solution. Journal of Chemical Information and Modeling,
-51(3), 739–753. \url{https://doi.org/10.1021/ci100384d}
+51(3), 739–753. \doi{10.1021/ci100384d}
 }
diff --git a/man/pan_query.Rd b/man/pan_query.Rd
index 2869440f..11d7bb09 100644
--- a/man/pan_query.Rd
+++ b/man/pan_query.Rd
@@ -27,7 +27,7 @@ pan_query(
 }
 \value{
 a named list of 73 entries,
-  see \url{http://www.pesticideinfo.org/Docs/ref_overview.html} for more information.
+  see \url{https://www.pesticideinfo.org/about/overview.html} for more information.
   If \code{match="best"} an additional entry \code{match_score} with the normalized
   Levenshtein distance (0 = perfect match, 1 = worst match).
 
@@ -64,7 +64,7 @@ Irrigation Water Guidelines (ug/L); Livestock Water Guidelines (ug/L);
 Chemical Name; matching synonym; source URL
 }
 \description{
-Retrieve information from the PAN database (\url{http://www.pesticideinfo.org/}).
+Retrieve information from the PAN database (\url{https://www.pesticideinfo.org/}).
 This function is currently broken.
 }
 \examples{
diff --git a/man/parse_mol.Rd b/man/parse_mol.Rd
index 593a7f1e..a2d43cdc 100644
--- a/man/parse_mol.Rd
+++ b/man/parse_mol.Rd
@@ -33,5 +33,5 @@ Parse Molfile (as returned by ChemSpider) into a R-object.
 Grabner, M., Varmuza, K., & Dehmer, M. (2012). RMol:
 a toolset for transforming SD/Molfile structure information into R objects.
 Source Code for Biology and Medicine, 7, 12.
-\url{https://doi.org/10.1186/1751-0473-7-12}
+\doi{10.1186/1751-0473-7-12}
 }
diff --git a/man/pc_prop.Rd b/man/pc_prop.Rd
index eec30b60..cd6d28ac 100644
--- a/man/pc_prop.Rd
+++ b/man/pc_prop.Rd
@@ -65,7 +65,7 @@ information in PubChem. Nucleic acids research, gkv396.
 Eduard Szöcs, Tamás Stirling, Eric R. Scott, Andreas Scharmüller,
 Ralf B. Schäfer (2020). webchem: An R Package to Retrieve Chemical
 Information from the Web. Journal of Statistical Software, 93(13).
-<doi:10.18637/jss.v093.i13>.
+\doi{10.18637/jss.v093.i13}.
 }
 \seealso{
 \code{\link{get_cid}}, \code{\link{pc_sect}}
diff --git a/man/pc_sect.Rd b/man/pc_sect.Rd
index 7c4d6536..c8646222 100644
--- a/man/pc_sect.Rd
+++ b/man/pc_sect.Rd
@@ -68,7 +68,7 @@ pc_sect("1ZHY_A", "Sequence", "protein")
 \references{
 Kim, S., Thiessen, P.A., Cheng, T. et al. PUG-View: programmatic
 access to chemical annotations integrated in PubChem. J Cheminform 11, 56
-(2019). https://doi.org/10.1186/s13321-019-0375-2.
+(2019). \doi{10.1186/s13321-019-0375-2}.
 }
 \seealso{
 \code{\link{get_cid}}, \code{\link{pc_prop}}
diff --git a/man/wd_ident.Rd b/man/wd_ident.Rd
index d753bfbb..9454f92a 100644
--- a/man/wd_ident.Rd
+++ b/man/wd_ident.Rd
@@ -30,7 +30,7 @@ only the first is returned.
 }
 \references{
 Willighagen, E., 2015. Getting CAS registry numbers out of WikiData. The Winnower.
-\url{http://dx.doi.org/10.15200/winn.142867.72538}
+\doi{10.15200/winn.142867.72538}
 
 Mitraka, Elvira, Andra Waagmeester, Sebastian Burgstaller-Muehlbacher, et al. 2015
 Wikidata: A Platform for Data Integration and Dissemination for the Life Sciences and beyond. bioRxiv: 031971.