diff --git a/.Rbuildignore b/.Rbuildignore
index 5084075d..b3f64100 100644
--- a/.Rbuildignore
+++ b/.Rbuildignore
@@ -15,4 +15,6 @@ tmp/
 revdep/
 ^codemeta\.json$
 ^tic.R$
-^.pre-commit-config.yaml$
\ No newline at end of file
+^.pre-commit-config.yaml$
+^.*\.Rproj$
+^\.Rproj\.user$
diff --git a/.gitignore b/.gitignore
index eae1c4e6..6d1efe09 100644
--- a/.gitignore
+++ b/.gitignore
@@ -18,3 +18,7 @@ revdep/
 README.html
 README_files/
 figure/
+.Rproj.user
+*.Rproj
+
+cit*.t*xt
diff --git a/DESCRIPTION b/DESCRIPTION
index 9d0d8e74..3ee31176 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -49,7 +49,7 @@ VignetteBuilder:
     knitr
 Encoding: UTF-8
 LazyData: true
-RoxygenNote: 6.1.99.9001
+RoxygenNote: 7.0.0
 X-schema.org-isPartOf: https://ropensci.org
 X-schema.org-keywords: metadata, ropensci, phylogenetics,
     independant-contrasts, biodiversity
diff --git a/NAMESPACE b/NAMESPACE
index 8a185da3..e4377723 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -1,6 +1,6 @@
 # Generated by roxygen2: do not edit by hand
 
-S3method(`[`,otl_ott_id)
+S3method("[",otl_ott_id)
 S3method(candidate_for_synth,study_meta)
 S3method(flags,match_names)
 S3method(flags,taxon_info)
@@ -63,6 +63,7 @@ S3method(unique_name,tol_summary)
 S3method(update,match_names)
 export(candidate_for_synth)
 export(flags)
+export(get_citations)
 export(get_publication)
 export(get_study)
 export(get_study_meta)
diff --git a/R/base.R b/R/base.R
index 7ee1ce9b..28a72351 100644
--- a/R/base.R
+++ b/R/base.R
@@ -208,3 +208,19 @@ check_label_format <- function(x) {
     return(FALSE)
   }
 }
+
+# res is an output from .tol_induced_subtree or .tol_subtree
+# returns a list with tree and study ids supporting a subtree
+studies_from_otl <- function(res){
+  if (is.list(res)) {
+    if (!is.null(res$supporting_studies)) {
+        studies <- res$supporting_studies
+    }
+    else {
+        stop("Cannot find supporting studies")
+    }
+  }
+  study_ids <- sapply(stringr::str_split(studies, "@"), '[', 1)
+  trees <- sapply(stringr::str_split(studies, "@"), '[', 2)
+  return(list(study_ids = study_ids, trees = trees))
+}
diff --git a/R/studies-methods.R b/R/studies-methods.R
index dad86309..500eb41a 100644
--- a/R/studies-methods.R
+++ b/R/studies-methods.R
@@ -87,3 +87,11 @@ candidate_for_synth.study_meta <- function(sm) {
 get_study_year.study_meta <- function(sm) {
   sm[["nexml"]][["^ot:studyYear"]]
 }
+
+##' Get citations for a set of study ids
+##' @export
+##' @param study_ids is a vector of study ids
+get_citations <- function(study_ids){
+  citations <- sapply(study_ids, function(x) get_publication.study_meta(get_study_meta(study_id = x)))
+  return(citations)
+}
diff --git a/R/tol.R b/R/tol.R
index c9369293..5dcf2b61 100644
--- a/R/tol.R
+++ b/R/tol.R
@@ -427,6 +427,8 @@ tol_subtree <- function(ott_id = NULL, node_id = NULL, label_format = NULL,
 ##'     (the default).
 ##' @param file If specified, the function will write the subtree to a file in
 ##'     newick format.
+##' @param file_citations If specified, the function will write citations from
+##'        supporting source trees to a txt file. It will automatically add the "txt" extension.
 ##' @param ... additional arguments to customize the API call (see
 ##'     \code{\link{rotl}} for more information).
 ##'
@@ -455,11 +457,28 @@ tol_subtree <- function(ott_id = NULL, node_id = NULL, label_format = NULL,
 ##' }
 ##' @export
 tol_induced_subtree <- function(ott_ids = NULL, node_ids = NULL, label_format = NULL,
-                                file, ...) {
+                                file, file_citations, ...) {
   res <- .tol_induced_subtree(
     ott_ids = ott_ids, node_ids = node_ids,
     label_format = label_format, ...
   )
+  # print citations
+  if (!missing(file_citations)) {
+    filecit <- paste0(file_citations, ".txt")
+    citations <- get_citations(studies_from_otl(res)$study_ids)
+    unlink(filecit)
+    cat(paste(citations, collapse = '\n\n'), file = filecit)
+    message(paste0("Citations were written to ", filecit, " in dir ", getwd()))
+  }
+  #   else {
+  #   # enhance: if file is not provided write to tmp dir
+  #   # tmpdir <- "temporary file dir"
+  #   # message(paste("'citations.txt' file has been written to dir", tmpdir))
+  #   filecit <- "citations.txt"
+  #   enhance: print to screen at leats part of citations, so users know that they're there.
+  # }
+
+
   if (!missing(file)) {
     unlink(file)
     cat(res$newick, file = file)
diff --git a/man/get_citations.Rd b/man/get_citations.Rd
new file mode 100644
index 00000000..661bdf59
--- /dev/null
+++ b/man/get_citations.Rd
@@ -0,0 +1,14 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/studies-methods.R
+\name{get_citations}
+\alias{get_citations}
+\title{Get citations for a set of study ids}
+\usage{
+get_citations(study_ids)
+}
+\arguments{
+\item{study_ids}{is a vector of study ids}
+}
+\description{
+Get citations for a set of study ids
+}
diff --git a/man/get_study_meta.Rd b/man/get_study_meta.Rd
index e98b83f0..fccfbd7a 100644
--- a/man/get_study_meta.Rd
+++ b/man/get_study_meta.Rd
@@ -31,12 +31,12 @@ get_study_year(sm)
 get_study_meta(study_id, ...)
 }
 \arguments{
+\item{sm}{an object created by \code{get_study_meta}}
+
 \item{study_id}{the study identifier (character)}
 
 \item{...}{additional arguments to customize the API request (see
 \code{\link{rotl}} package documentation).}
-
-\item{sm}{an object created by \code{get_study_meta}}
 }
 \value{
 named-list containing the metadata associated with the
diff --git a/man/list_trees.Rd b/man/list_trees.Rd
index f53d3343..d7ffa93e 100644
--- a/man/list_trees.Rd
+++ b/man/list_trees.Rd
@@ -15,10 +15,10 @@ list_trees(matched_studies, ...)
 \item{matched_studies}{an object created by
 \code{studies_find_trees} or \code{studies_find_studies}.}
 
+\item{...}{Currently unused}
+
 \item{study_id}{a \code{study_id} listed in the object returned by
 \code{studies_find_trees}}
-
-\item{...}{Currently unused}
 }
 \value{
 \code{list_trees} returns a list of the tree_ids for each
diff --git a/man/strip_ott_ids.Rd b/man/strip_ott_ids.Rd
index 056821ce..b1e202ef 100644
--- a/man/strip_ott_ids.Rd
+++ b/man/strip_ott_ids.Rd
@@ -25,8 +25,8 @@ Strip OTT ids from tip labels
 \dontrun{
 genera <- c("Perdix", "Setophaga", "Cinclus", "Struthio")
 tr <- tol_induced_subtree(ott_ids=c(102710, 285198, 267845, 292466))
-tr$tip.label \%in\% genera
+tr$tip.label %in% genera
 tr$tip.label <- strip_ott_ids(tr$tip.label)
-tr$tip.label \%in\% genera
+tr$tip.label %in% genera
 }
 }
diff --git a/man/tol_induced_subtree.Rd b/man/tol_induced_subtree.Rd
index 25443b77..ccedc4bd 100644
--- a/man/tol_induced_subtree.Rd
+++ b/man/tol_induced_subtree.Rd
@@ -9,6 +9,7 @@ tol_induced_subtree(
   node_ids = NULL,
   label_format = NULL,
   file,
+  file_citations,
   ...
 )
 }
@@ -26,6 +27,9 @@ tips in the induced tree.}
 \item{file}{If specified, the function will write the subtree to a file in
 newick format.}
 
+\item{file_citations}{If specified, the function will write citations from
+supporting source trees to a txt file. It will automatically add the "txt" extension.}
+
 \item{...}{additional arguments to customize the API call (see
 \code{\link{rotl}} for more information).}
 }
diff --git a/man/tol_node_info.Rd b/man/tol_node_info.Rd
index 6d2ac5aa..b1e7f05a 100644
--- a/man/tol_node_info.Rd
+++ b/man/tol_node_info.Rd
@@ -34,17 +34,17 @@ tol_node_info(ott_id = NULL, node_id = NULL, include_lineage = FALSE, ...)
 \method{tol_lineage}{tol_node}(tax, ...)
 }
 \arguments{
+\item{tax}{an object returned by \code{tol_node_info}.}
+
+\item{...}{additional arguments to customize the API call (see
+?rotl for more information)}
+
 \item{ott_id}{Numeric. The OpenTree taxonomic identifier.}
 
 \item{node_id}{Character. The OpenTree node identifier.}
 
 \item{include_lineage}{Logical (default = FALSE). Whether to return the
 lineage of the node from the synthetic tree.}
-
-\item{...}{additional arguments to customize the API call (see
-?rotl for more information)}
-
-\item{tax}{an object returned by \code{tol_node_info}.}
 }
 \value{
 \code{tol_node_info} returns an invisible list of summary