diff --git a/R/class-endpoint.R b/R/class-endpoint.R
index 7fd1e45..3ef379b 100644
--- a/R/class-endpoint.R
+++ b/R/class-endpoint.R
@@ -173,10 +173,11 @@ random.Timeseries <- function(e) {
 
 #' Example API endpoints.
 #'
-#' \code{sensorweb_api_endpoints} returns an instance of \linkS4class{Endpoint}
+#' \code{example.endpoints} returns an instance of \linkS4class{Endpoint}
 #' that can be used for testing.
-#'
-#' @return R object with the further endpoints offered by the service
+#' @param the optional name of the endpoint
+#' @return R object with the further endpoints offered by the service or the
+#'         endpoint with the specified name
 #' @author Daniel Nuest \email{d.nuest@@52north.org}
 #' @author Christian Autermann \email{c.autermann@@52north.org}
 #'
@@ -185,10 +186,18 @@ random.Timeseries <- function(e) {
 #' @examples
 #' example.endpoints()
 #' services(example.endpoints()[1])
-example.endpoints <- function() {
-    Endpoint(url = c("http://sensorweb.demo.52north.org/sensorwebclient-webapp-stable/api/v1/",
-                     "http://sosrest.irceline.be/api/v1/",
-                     "http://www.fluggs.de/sos2/api/v1/",
-                     "http://sensors.geonovum.nl/sos/api/v1/"),
-             label = c("52N Demo", "IRCEL-CELINE", "WV", "Geonovum"))
+#' example.endpoints("UoL")
+example.endpoints <- function(name) {
+    e <- Endpoint(url = c("http://sensorweb.demo.52north.org/sensorwebclient-webapp-stable/api/v1/",
+                          "http://sosrest.irceline.be/api/v1/",
+                          "http://www.fluggs.de/sos2/api/v1/",
+                          "http://sensors.geonovum.nl/sos/api/v1/",
+                          "http://www57.lamp.le.ac.uk/52n-sos-webapp/api/v1/"),
+                  label = c("52N Demo",
+                            "IRCEL-CELINE",
+                            "WV",
+                            "Geonovum",
+                            "UoL"))
+    if (missing(name)) e
+    else e[label(e) == name]
 }
diff --git a/R/class-service.R b/R/class-service.R
index 27c8b90..001d466 100644
--- a/R/class-service.R
+++ b/R/class-service.R
@@ -43,9 +43,8 @@ Service <- function(id = character(),
                     supportsFirstLatest = NULL,
                     quantities = NULL,
                     endpoint = NULL) {
-
+    id <- as.character(id)
     len <- length(id)
-
     label <- stretch(len, label, as.character(NA), as.character)
     serviceURL <- stretch(len, serviceURL, as.character(NA), as.character)
     version <- stretch(len, version, as.character(NA), as.character)
diff --git a/R/query-methods.R b/R/query-methods.R
index ecac30a..5cd84ad 100644
--- a/R/query-methods.R
+++ b/R/query-methods.R
@@ -21,7 +21,14 @@ stop.if.no.query <- function(query) {
 
 as.parameter.list <- function(x) {
     if (is.null(x) || length(x) == 0) NULL
-    else paste(x, collapse=",")
+    else paste(x, collapse = ",")
+}
+
+getIds <- function(x, ...) {
+    ids <- path(x, ...)
+    ids <- sapply(ids, function(x)
+        if (is.null(x) || is.na(x)) NA else x)
+    as.character(ids)
 }
 
 #' Query Helper
@@ -80,33 +87,34 @@ as.query.string <- function(...) {
 
 fetch.resourceURL <- function(x, ...) {
     args <-  list(...)
-    query <- if(is.null(args$query)) list()
+    query <- if (is.null(args$query)) list()
     else do.call(as.query.string, args$query)
 
     tofetch <- unique(x)
-
-    lapply(tofetch[!(paste(tofetch, query, sep="?") %in% get.cache.keys())],
+    cached <- paste(tofetch, query, sep = "?") %in% get.cache.keys()
+    tofetch <- tofetch[!cached]
+    lapply(tofetch,
            function(url) {
-               key <- paste(url, query, sep="?")
-               value <- get.json(url, ...)
+               key <- paste(url, query, sep = "?")
+               value <- if (is.na(url)) list() else get.json(url, ...)
                set.cache.value(key, value)
            })
-
-    lapply(paste(x, query, sep="?"),
+    lapply(paste(x, query, sep = "?"),
            function(url) get.cache.value(url))
 }
 
 get.json <- function(url, ...) {
+    if (is.null(url) || is.na(url)) return(NULL)
     p <- list(...)
     q <- ifelse(!is.null(p$query), do.call(as.query.string, p$query), "")
     futile.logger::flog.debug("Requesting %s?%s", url, q)
-    response <- httr::GET(url, httr::add_headers(Accept="application/json"), ...)
+    response <- httr::GET(url, httr::add_headers(Accept = "application/json"), ...)
     content <- httr::content(response, "text")
-
     tryCatch(httr::stop_for_status(response),
              error = function(err) {
-                 message <- paste0("Error requesting '",url,"?",q,"': ", err, "\n", content)
-                 futile.logger::flog.error(message);
+                 if (httr::status_code(response) == 404) return(NULL)
+                 message <- paste0("Error requesting '", url, "?", q, "': ", err, "\n", content)
+                 futile.logger::flog.error(message);    str(url)
                  stop(message)
              })
 
@@ -118,13 +126,13 @@ get.and.parse <- function(endpoint, query, fun.url, fun.parse)
 
 
 path <- function(x, path, ...) {
-    x <- lapply(x, "[[", path)
+    x <- lapply(x, '[[', path)
     if (nargs() == 2) x else Recall(x, ...)
 }
 
 simplify.list <- function(x, path) {
     if (!missing(path)) x <- lapply(x, "[[", path)
-    do.call(mapply, c(list(FUN=c, SIMPLIFY=F), x))
+    do.call(mapply, c(list(FUN = c, SIMPLIFY = F), x))
 }
 
 #' @rdname query-methods
@@ -287,12 +295,19 @@ setMethod("fetch",
           function(x, ...) {
               tmp <- fetch.resource(x)
               fetched <- simplify.list(tmp)
-              label(x) <- fetched$label
-              serviceURL(x) <- fetched$serviceUrl
-              version(x) <- fetched$version
-              type(x) <- fetched$type
+              label(x) <- as.character(fetched$label)
+              serviceURL(x) <- as.character(fetched$serviceUrl)
+              version(x) <- as.character(fetched$version)
+              type(x) <- as.character(fetched$type)
               supportsFirstLatest(x) <- as.logical(fetched$supportsFirstLatest)
-              quantities(x) <- as.data.frame(t(sapply(tmp, "[[", "quantities")))
+
+              quantities <- lapply(tmp, "[[", "quantities")
+              quantities <- lapply(quantities, function(x)
+                  if (is.null(x) || is.na(x))
+                      default.quantities(1)
+                  else as.data.frame(t(x))
+              )
+              quantities(x) <- do.call(rbind, quantities)
               x
           })
 
@@ -304,8 +319,8 @@ setMethod("fetch",
               fetched <- simplify.list(tmp)
               service <- Service(endpoint = endpoint(x),
                                  id = simplify.list(tmp, "service")$id)
-              label(x) <- fetched$label
-              domainId(x) <- fetched$domainId
+              label(x) <- as.character(fetched$label)
+              domainId(x) <- as.character(fetched$domainId)
               service(x) <- fetch(service)
               x
           })
@@ -315,10 +330,11 @@ setMethod("fetch",
           signature(x = "Category"),
           function(x, ...) {
               tmp <- fetch.resource(x)
+
               fetched <- simplify.list(tmp)
-              service <- Service(endpoint = endpoint(x),
-                                 id = simplify.list(tmp, "service")$id)
-              label(x) <- fetched$label
+              service <- getIds(tmp, "service", "id")
+              service <- Service(endpoint = endpoint(x), id = service)
+              label(x) <- as.character(fetched$label)
               service(x) <- fetch(service)
               x
           })
@@ -342,26 +358,26 @@ setMethod("fetch",
           function(x, ...) {
               tmp <- fetch.resource(x)
 
-              label(x) <- as.character(path(tmp, "label"))
-              uom(x) <- as.character(path(tmp, "uom"))
+              label(x) <- sapply(path(tmp, "label"), as.character)
+              uom(x) <- sapply(path(tmp, "uom"), as.character)
 
-              station(x) <- fetch(Station(id = as.character(path(tmp, "station", "properties", "id")), endpoint = endpoint(x)))
-              service(x) <- fetch(Service(id = as.character(path(tmp, "parameters", "service", "id")), endpoint = endpoint(x)))
-              offering(x) <- fetch(Offering(id = as.character(path(tmp, "parameters", "offering", "id")), endpoint = endpoint(x)))
-              #feature(x) <- fetch(Feature(id = as.character(path(tmp, "parameters", "feature", "id")), endpoint = endpoint(x)))
-              procedure(x) <- fetch(Procedure(id = as.character(path(tmp, "parameters", "procedure", "id")), endpoint = endpoint(x)))
-              phenomenon(x) <- fetch(Phenomenon(id = as.character(path(tmp, "parameters", "phenomenon", "id")), endpoint = endpoint(x)))
-              category(x) <- fetch(Category(id = as.character(path(tmp, "parameters", "category", "id")), endpoint = endpoint(x)))
+              station(x) <- fetch(Station(id = getIds(tmp, "station", "properties", "id"), endpoint = endpoint(x)))
+              service(x) <- fetch(Service(id = getIds(tmp, "parameters", "service", "id"), endpoint = endpoint(x)))
+              feature(x) <- fetch(Feature(id = getIds(tmp, "parameters", "feature", "id"), endpoint = endpoint(x)))
+              offering(x) <- fetch(Offering(id = getIds(tmp, "parameters", "offering", "id"), endpoint = endpoint(x)))
+              procedure(x) <- fetch(Procedure(id = getIds(tmp, "parameters", "procedure", "id"), endpoint = endpoint(x)))
+              phenomenon(x) <- fetch(Phenomenon(id = getIds(tmp, "parameters", "phenomenon", "id"), endpoint = endpoint(x)))
+              category(x) <- fetch(Category(id = getIds(tmp, "parameters", "category", "id"), endpoint = endpoint(x)))
 
               list.as.numeric <- function(x)
                   sapply(x, function(x)
-                      if(is.null(x)) NA else x)
+                      if (is.null(x)) NA else x)
 
               list.as.tvp <- function(x) {
                   ts <- list.as.numeric(path(x, "timestamp"))
                   v <- list.as.numeric(path(x, "value"))
                   values <- list(timestamp = ts, value = v)
-                  TimeseriesData.parse(list(values=values))
+                  TimeseriesData.parse(list(values = values))
               }
 
               list.as.rv <- function(x) {
@@ -376,6 +392,7 @@ setMethod("fetch",
 
               x
           })
+
 #' @param generalize Generalize the data on server side.
 #' @rdname query-methods
 setMethod("getData",
@@ -385,6 +402,6 @@ setMethod("getData",
                    timespan = NULL, ...) {
               query <- list(generalize = as.logical.parameter(generalize),
                             timespan = as.timespan.parameter(timespan))
-              tmp <- fetch.resourceURL(getDataURL(x), query=query)
+              tmp <- fetch.resourceURL(getDataURL(x), query = query)
               lapply(tmp, TimeseriesData.parse)
           });
diff --git a/R/virtual-class-api-resource.R b/R/virtual-class-api-resource.R
index bf51f20..75c541b 100644
--- a/R/virtual-class-api-resource.R
+++ b/R/virtual-class-api-resource.R
@@ -170,8 +170,13 @@ setMethod("resourceURL",
           signature(x = "ApiResource"),
           function(x) {
               if (length(x) == 0) return(character())
-              paste(resourceURL(endpoint(x)),
-                    collection.name(x),
-                    id(x),
-                    sep = "/")
+              ifelse(is.na(x), NA,
+                     paste(resourceURL(endpoint(x)),
+                           collection.name(x),
+                           id(x),
+                           sep = "/"))
           })
+
+setMethod("is.na",
+          signature(x = "ApiResource"),
+          function(x) is.na(id(x)))
diff --git a/man/example.endpoints.Rd b/man/example.endpoints.Rd
index e870d03..a5dc8bd 100644
--- a/man/example.endpoints.Rd
+++ b/man/example.endpoints.Rd
@@ -4,18 +4,23 @@
 \alias{example.endpoints}
 \title{Example API endpoints.}
 \usage{
-example.endpoints()
+example.endpoints(name)
+}
+\arguments{
+\item{the}{optional name of the endpoint}
 }
 \value{
-R object with the further endpoints offered by the service
+R object with the further endpoints offered by the service or the
+        endpoint with the specified name
 }
 \description{
-\code{sensorweb_api_endpoints} returns an instance of \linkS4class{Endpoint}
+\code{example.endpoints} returns an instance of \linkS4class{Endpoint}
 that can be used for testing.
 }
 \examples{
 example.endpoints()
 services(example.endpoints()[1])
+example.endpoints("UoL")
 }
 \author{
 Daniel Nuest \email{d.nuest@52north.org}