diff --git a/configure.ac b/configure.ac
index 2b9643f..ae24f4b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -20,145 +20,88 @@ AC_SUBST([VERSION_MAJOR])
 AC_SUBST([VERSION_MINOR])
 AC_SUBST([VERSION_PATCH])
 
-# Checks for programs.
+
+
+## -------------------
+## Checks for programs 
+## -------------------
+
 AC_LANG(C)
 AC_PROG_CC
-# Make sure the c compiler supports C99
+
+# C99 support
 m4_version_prereq([2.70],[], [AC_PROG_CC_C99])
-AS_IF([test "$ac_cv_prog_cc_c99" = "no"], [AC_MSG_ERROR([The compiler does not support C99])])
+AS_IF([test "$ac_cv_prog_cc_c99" = "no"],
+      [AC_MSG_ERROR([The compiler does not support C99])])
 AC_PROG_CC_C_O
 
+# Fortran
 AC_PROG_FC
 AC_FC_FREEFORM
 AC_FC_SRCEXT([f90])
-
 AC_PROG_FC_C_O
+AC_FC_LIBRARY_LDFLAGS
+
+# pkg-config
+PKG_PROG_PKG_CONFIG()
+PKG_CFLAGS=""
+
 AC_PROG_INSTALL
 AC_PROG_LIBTOOL
 AC_PROG_LN_S
-PKG_PROG_PKG_CONFIG()
-PKG_LIBS=""
-PKG_CFLAGS=""
-
-AC_FC_LIBRARY_LDFLAGS
 
 
+## ---------
+## Libraries
+## ---------
 
-# Configure with HDF5 (default: --with-hdf5 using pkg-config) [optional]:
-# ./configure [--with-hdf5 or --with-hdf5=yes]
-# Configure with user-provided path to HDF5:
-# ./configure --with-hdf5=/usr/lib/x86_64-linux-gnu/hdf5/serial
-# Configure without HDF5:
-# ./configure --without-hdf5 [or --with-hdf5=no]
-
-# when configure complains about missing install-sh or install.sh, execute:
-# automake --add-missing --copy
-
-# Checks for basic libraries.
-AC_CHECK_LIB([m], [sqrt])
 # Checks for basic header files.
 AC_CHECK_HEADERS([fcntl.h inttypes.h stdint.h stdlib.h string.h unistd.h])
 
-# Search for pthread
-have_pthreads=no
-AC_SEARCH_LIBS([pthread_create], [pthread], [have_pthreads=yes])
 
-if test "x${have_pthreads}" = xyes; then
-   AC_CHECK_HEADERS([pthread.h], [], [have_pthreads=no])
-   PKG_LIBS="${PKG_LIBS} -lpthread"
-fi
+### HDF5
+### ----
 
-if test "x${have_pthreads}" = xno; then
-AC_MSG_ERROR([
-	------------------------------------------
-	The pthread library and header file
-	required to build TREXIO. Stopping...
-	Check 'config.log' for more information.
-	------------------------------------------])
-fi
+# Configure with HDF5 (default: --with-hdf5 using pkg-config) [optional]:
+# ./configure [--with-hdf5 or --with-hdf5=yes]
+
+# Configure with user-provided path to HDF5:
+# ./configure --with-hdf5=/usr/lib/x86_64-linux-gnu/hdf5/serial
+
+# Configure without HDF5:
+# ./configure --without-hdf5 [or --with-hdf5=no]
 
-AC_ARG_WITH([hdf5],
-	    AS_HELP_STRING([--with-hdf5],
-			   [Include HDF5 functionality @<:@default: yes@:>@])],
-	     [hdf5=${withval}],
-	     [hdf5=yes])
 
 PKG_HDF5=""
-if test "x${hdf5}" = xno; then
+AX_LIB_HDF5([serial])
+
+if test "x${with_hdf5}" = xno; then
   AC_MSG_WARN([
     ------------------------------------------
     Configuring with the HDF5 library is
     recommended to build efficient TREXIO.
     ------------------------------------------])
-
-elif test "x${hdf5}" = xyes; then
-
-  # Check if HDF5 is already configured (e.g. after calling `module load hdf5-<version>`)
-  AC_CHECK_HEADERS([hdf5_hl.h])
-  AC_CHECK_LIB([hdf5_hl], [H5LTfind_dataset], [], [have_hdf5_hl=no])
-
-  AC_CHECK_HEADERS([hdf5.h])
-  AC_CHECK_LIB([hdf5], [H5open], [], [have_hdf5=no])
-
-  if test "x${have_hdf5}" = xno; then
-    # If HDF5 is not configured, try using pkg-config
-    PKG_CHECK_MODULES([HDF5], [hdf5 >= 1.8])
-    CFLAGS="$(pkg-config --cflags hdf5) ${CFLAGS}"
-    LDFLAGS="$(pkg-config --libs hdf5) -lhdf5_hl ${LDFLAGS}"
-    PKG_HDF5="hdf5"
-    PKG_LIBS="${PKG_LIBS} -lhdf5_hl"
-  else
-    PKG_HDF5=""
-    PKG_LIBS="${PKG_LIBS} ${HDF5_LIBS} -lhdf5_hl"
-    PKG_CFLAGS="${PKG_CFLAGS} ${HDF5_CFLAGS}"
-    CFLAGS="${HDF5_LIBS}  ${CFLAGS}"
-    LDFLAGS="${HDF5_CFLAGS} -lhdf5_hl ${LDFLAGS}"
-  fi
-
-else
-
-  if test "x${hdf5}" = x; then
-    AC_MSG_ERROR([
-    ------------------------------------------
-    The path to HDF5 library is required.
-    Maybe you forgot to pass --with-hdf5="/your/path/" to configure script.
-    Stopping...
-    ------------------------------------------])
-  fi
-
-  CPPFLAGS="-I${hdf5}/include ${CPPFLAGS}"
-  LDFLAGS="-L${hdf5} ${LDFLAGS}"
-
-  AC_CHECK_HEADERS([hdf5_hl.h])
-  AC_CHECK_LIB([hdf5_hl], [H5LTfind_dataset], [], [have_hdf5_hl=no])
-
-  AC_CHECK_HEADERS([hdf5.h])
-  AC_CHECK_LIB([hdf5], [H5open], [], [have_hdf5=no])
-
-  PKG_HDF5=""
-  PKG_LIBS="${PKG_LIBS} -L${hdf5} -lhdf5_hl"
-  PKG_CFLAGS="${PKG_CFLAGS} -I${hdf5}/include"
 fi
+
+CFLAGS="${HDF5_CFLAGS} ${CFLAGS}"
+CPPFLAGS="${HDF5_CPPFLAGS} ${CPPFLAGS}"
+LDFLAGS="${HDF5_LDFLAGS} ${LDFLAGS}"
+LIBS="${HDF5_LIBS} ${LIBS}"
+
+
+# Check if hdf5 if available with pkg-config
+
+PKG_CHECK_MODULES([HDF5], [hdf5 >= 1.8], [
+    PKG_HDF5="hdf5"
+    ],[
+    PKG_HDF5=""
+   ])
+    PKG_CFLAGS="${PKG_CFLAGS}"
+
 AC_SUBST([PKG_HDF5])
-AC_SUBST([PKG_LIBS])
 AC_SUBST([PKG_CFLAGS])
 
 
-# add -fPIC if not present in CFLAGS, necessary to compile TREXIO
-# TODO: replace with AM_CFLAGS for appropriate targer once Automake is introduced
-case "${CFLAGS}" in
-    *-fPIC*)
-    ;;
-    *)
-    AC_MSG_WARN([
-    ------------------------------------------
-    Adding -fPIC option to CFLAGS.
-    This is necessary to build TREXIO.
-    ------------------------------------------])
-    CFLAGS="${CFLAGS} -fPIC"
-    ;;
-esac
-
 # Checks for typedefs, structures, and compiler characteristics.
 AC_TYPE_INT32_T
 AC_TYPE_INT64_T
@@ -194,6 +137,19 @@ if test "x${TREXIO_DEVEL}" != "x"; then
 
 fi
 
+## Libm
+## ----
+
+AC_SEARCH_LIBS([sqrt], [m], [], AC_MSG_ERROR([The libm library is required]))
+AC_CHECK_HEADERS([math.h])
+
+### pthread
+### -------
+
+AC_SEARCH_LIBS([pthread_create], [pthread], [], AC_MSG_ERROR([The pthread library is required]))
+AC_CHECK_HEADERS([pthread.h])
+
+
 AC_CONFIG_FILES([Makefile
                  pkgconfig/trexio.pc])
 AC_OUTPUT
@@ -203,23 +159,22 @@ echo \
 
 ${PACKAGE_NAME} Version ${PACKAGE_VERSION} ${TREXIO_DEVEL}
 
-Prefix: '${prefix}'.
-
-CC:           ${CC}
-CPPFLAGS:     ${CPPFLAGS}
-CFLAGS:	      ${CFLAGS}
-FC:           ${FC}
-FCLAGS:       ${FCFLAGS}
-LDFLAGS:      ${LDFLAGS}
-LIBS:         ${LIBS}
+Prefix ........:  ${prefix}
+CC ............:  ${CC}
+CPPFLAGS ......:  ${CPPFLAGS}
+CFLAGS ........:  ${CFLAGS}
+FC ............:  ${FC}
+FCLAGS ........:  ${FCFLAGS}
+LDFLAGS .......:  ${LDFLAGS}
+LIBS ..........:  ${LIBS}
 
 Package features:
-  Compilation with HDF5: ${hdf5}
+  Compilation with HDF5: ${with_hdf5}
 
 Now type 'make @<:@<target>@:>@'
 where the optional <target> is:
-  all           - build C and Fortran APIs
-  check	        - check C and Fortran APIs
-  clean         - clean the produced files
+  all           - build C library and Fortran binding
+  check	        - run unit tests
+  install       - install the library 
 --------------------------------------------------"
 
diff --git a/m4/ax_lib_hdf5.m4 b/m4/ax_lib_hdf5.m4
new file mode 100644
index 0000000..074c2a8
--- /dev/null
+++ b/m4/ax_lib_hdf5.m4
@@ -0,0 +1,323 @@
+# ===========================================================================
+#       https://www.gnu.org/software/autoconf-archive/ax_lib_hdf5.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_LIB_HDF5([serial/parallel])
+#
+# DESCRIPTION
+#
+#   This macro provides tests of the availability of HDF5 library.
+#
+#   The optional macro argument should be either 'serial' or 'parallel'. The
+#   former only looks for serial HDF5 installations via h5cc. The latter
+#   only looks for parallel HDF5 installations via h5pcc. If the optional
+#   argument is omitted, serial installations will be preferred over
+#   parallel ones.
+#
+#   The macro adds a --with-hdf5 option accepting one of three values:
+#
+#     no   - do not check for the HDF5 library.
+#     yes  - do check for HDF5 library in standard locations.
+#     path - complete path to the HDF5 helper script h5cc or h5pcc.
+#
+#   If HDF5 is successfully found, this macro calls
+#
+#     AC_SUBST(HDF5_VERSION)
+#     AC_SUBST(HDF5_CC)
+#     AC_SUBST(HDF5_CFLAGS)
+#     AC_SUBST(HDF5_CPPFLAGS)
+#     AC_SUBST(HDF5_LDFLAGS)
+#     AC_SUBST(HDF5_LIBS)
+#     AC_SUBST(HDF5_FC)
+#     AC_SUBST(HDF5_FFLAGS)
+#     AC_SUBST(HDF5_FLIBS)
+#     AC_SUBST(HDF5_TYPE)
+#     AC_DEFINE(HAVE_HDF5)
+#
+#   and sets with_hdf5="yes".  Additionally, the macro sets
+#   with_hdf5_fortran="yes" if a matching Fortran wrapper script is found.
+#   Note that Autoconf's Fortran support is not used to perform this check.
+#   H5CC and H5FC will contain the appropriate serial or parallel HDF5
+#   wrapper script locations.
+#
+#   If HDF5 is disabled or not found, this macros sets with_hdf5="no" and
+#   with_hdf5_fortran="no".
+#
+#   Your configuration script can test $with_hdf to take any further
+#   actions. HDF5_{C,CPP,LD}FLAGS may be used when building with C or C++.
+#   HDF5_F{FLAGS,LIBS} should be used when building Fortran applications.
+#
+#   To use the macro, one would code one of the following in "configure.ac"
+#   before AC_OUTPUT:
+#
+#     1) dnl Check for HDF5 support
+#        AX_LIB_HDF5()
+#
+#     2) dnl Check for serial HDF5 support
+#        AX_LIB_HDF5([serial])
+#
+#     3) dnl Check for parallel HDF5 support
+#        AX_LIB_HDF5([parallel])
+#
+#   One could test $with_hdf5 for the outcome or display it as follows
+#
+#     echo "HDF5 support:  $with_hdf5"
+#
+#   You could also for example, override the default CC in "configure.ac" to
+#   enforce compilation with the compiler that HDF5 uses:
+#
+#     AX_LIB_HDF5([parallel])
+#     if test "$with_hdf5" = "yes"; then
+#             CC="$HDF5_CC"
+#     else
+#             AC_MSG_ERROR([Unable to find HDF5, we need parallel HDF5.])
+#     fi
+#
+#   The HDF5_TYPE environment variable returns "parallel" or "serial",
+#   depending on which type of library is found.
+#
+# LICENSE
+#
+#   Copyright (c) 2009 Timothy Brown <tbrown@freeshell.org>
+#   Copyright (c) 2010 Rhys Ulerich <rhys.ulerich@gmail.com>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 20
+
+AC_DEFUN([AX_LIB_HDF5], [
+
+AC_REQUIRE([AC_PROG_SED])
+AC_REQUIRE([AC_PROG_AWK])
+AC_REQUIRE([AC_PROG_GREP])
+
+dnl Check first argument is one of the recognized values.
+dnl Fail eagerly if is incorrect as this simplifies case statements below.
+if   test "m4_normalize(m4_default([$1],[]))" = ""        ; then
+    : # Recognized value
+elif test "m4_normalize(m4_default([$1],[]))" = "serial"  ; then
+    : # Recognized value
+elif test "m4_normalize(m4_default([$1],[]))" = "parallel"; then
+    : # Recognized value
+else
+    AC_MSG_ERROR([
+Unrecognized value for AX[]_LIB_HDF5 within configure.ac.
+If supplied, argument 1 must be either 'serial' or 'parallel'.
+])
+fi
+
+dnl Add a default --with-hdf5 configuration option.
+AC_ARG_WITH([hdf5],
+  AS_HELP_STRING(
+    [--with-hdf5=[yes/no/PATH]],
+    m4_case(m4_normalize([$1]),
+            [serial],   [location of h5cc for serial HDF5 configuration],
+            [parallel], [location of h5pcc for parallel HDF5 configuration],
+            [location of h5cc or h5pcc for HDF5 configuration])
+  ),
+  [if test "$withval" = "no"; then
+     with_hdf5="no"
+   elif test "$withval" = "yes"; then
+     with_hdf5="yes"
+   else
+     with_hdf5="yes"
+     H5CC="$withval"
+   fi],
+   [with_hdf5="yes"]
+)
+
+dnl Set defaults to blank
+HDF5_CC=""
+HDF5_VERSION=""
+HDF5_CFLAGS=""
+HDF5_CPPFLAGS=""
+HDF5_LDFLAGS=""
+HDF5_LIBS=""
+HDF5_FC=""
+HDF5_FFLAGS=""
+HDF5_FLIBS=""
+HDF5_TYPE=""
+
+dnl Try and find hdf5 compiler tools and options.
+if test "$with_hdf5" = "yes"; then
+    if test -z "$H5CC"; then
+        dnl Check to see if H5CC is in the path.
+        AC_PATH_PROGS(
+            [H5CC],
+            m4_case(m4_normalize([$1]),
+                [serial],   [h5cc],
+                [parallel], [h5pcc],
+                [h5cc h5pcc]),
+            [])
+    else
+        AC_MSG_CHECKING([Using provided HDF5 C wrapper])
+        AC_MSG_RESULT([$H5CC])
+    fi
+    AC_MSG_CHECKING([for HDF5 type])
+    AS_CASE([$H5CC],
+        [*h5pcc], [HDF5_TYPE=parallel],
+        [*h5cc], [HDF5_TYPE=serial],
+        [HDF5_TYPE=neither])
+    AC_MSG_RESULT([$HDF5_TYPE])
+    AC_MSG_CHECKING([for HDF5 libraries])
+    if test ! -f "$H5CC" || test ! -x "$H5CC"; then
+        AC_MSG_RESULT([no])
+        AC_MSG_WARN(m4_case(m4_normalize([$1]),
+            [serial],  [
+Unable to locate serial HDF5 compilation helper script 'h5cc'.
+Please specify --with-hdf5=<LOCATION> as the full path to h5cc.
+HDF5 support is being disabled (equivalent to --with-hdf5=no).
+],            [parallel],[
+Unable to locate parallel HDF5 compilation helper script 'h5pcc'.
+Please specify --with-hdf5=<LOCATION> as the full path to h5pcc.
+HDF5 support is being disabled (equivalent to --with-hdf5=no).
+],            [
+Unable to locate HDF5 compilation helper scripts 'h5cc' or 'h5pcc'.
+Please specify --with-hdf5=<LOCATION> as the full path to h5cc or h5pcc.
+HDF5 support is being disabled (equivalent to --with-hdf5=no).
+]))
+        with_hdf5="no"
+        with_hdf5_fortran="no"
+    else
+        dnl Get the h5cc output
+        HDF5_SHOW=$(eval $H5CC -show)
+
+        dnl Get the actual compiler used
+        HDF5_CC=$(eval $H5CC -show | head -n 1 | $AWK '{print $[]1}')
+        if test "$HDF5_CC" = "ccache"; then
+            HDF5_CC=$(eval $H5CC -show | head -n 1 | $AWK '{print $[]2}')
+        fi
+
+        dnl h5cc provides both AM_ and non-AM_ options
+        dnl depending on how it was compiled either one of
+        dnl these are empty. Lets roll them both into one.
+
+        dnl Look for "HDF5 Version: X.Y.Z"
+        HDF5_VERSION=$(eval $H5CC -showconfig | $GREP 'HDF5 Version:' \
+            | $AWK '{print $[]3}')
+
+        dnl A ideal situation would be where everything we needed was
+        dnl in the AM_* variables. However most systems are not like this
+        dnl and seem to have the values in the non-AM variables.
+        dnl
+        dnl We try the following to find the flags:
+        dnl (1) Look for "NAME:" tags
+        dnl (2) Look for "H5_NAME:" tags
+        dnl (3) Look for "AM_NAME:" tags
+        dnl
+        HDF5_tmp_flags=$(eval $H5CC -showconfig \
+            | $GREP 'FLAGS\|Extra libraries:' \
+            | $AWK -F: '{printf("%s "), $[]2}' )
+
+        dnl Find the installation directory and append include/
+        HDF5_tmp_inst=$(eval $H5CC -showconfig \
+            | $GREP 'Installation point:' \
+            | $AWK '{print $[]NF}' )
+
+        dnl Add this to the CPPFLAGS
+        HDF5_CPPFLAGS="-I${HDF5_tmp_inst}/include"
+
+        dnl Now sort the flags out based upon their prefixes
+        for arg in $HDF5_SHOW $HDF5_tmp_flags ; do
+          case "$arg" in
+            -I*) echo $HDF5_CPPFLAGS | $GREP -e "$arg" 2>&1 >/dev/null \
+                  || HDF5_CPPFLAGS="$HDF5_CPPFLAGS $arg"
+              ;;
+            -L*) echo $HDF5_LDFLAGS | $GREP -e "$arg" 2>&1 >/dev/null \
+                  || HDF5_LDFLAGS="$HDF5_LDFLAGS $arg"
+              ;;
+            -l*) echo $HDF5_LIBS | $GREP -e "$arg" 2>&1 >/dev/null \
+                  || HDF5_LIBS="$HDF5_LIBS $arg"
+              ;;
+          esac
+        done
+
+        HDF5_LIBS="-lhdf5 $HDF5_LIBS"
+        AC_MSG_RESULT([yes (version $[HDF5_VERSION])])
+
+        dnl See if we can compile
+        AC_LANG_PUSH([C])
+        ax_lib_hdf5_save_CC=$CC
+        ax_lib_hdf5_save_CPPFLAGS=$CPPFLAGS
+        ax_lib_hdf5_save_LIBS=$LIBS
+        ax_lib_hdf5_save_LDFLAGS=$LDFLAGS
+        CC=$HDF5_CC
+        CPPFLAGS=$HDF5_CPPFLAGS
+        LIBS=$HDF5_LIBS
+        LDFLAGS=$HDF5_LDFLAGS
+        AC_CHECK_HEADER([hdf5.h], [ac_cv_hadf5_h=yes], [ac_cv_hadf5_h=no])
+        AC_CHECK_LIB([hdf5], [H5Fcreate], [ac_cv_libhdf5=yes],
+                     [ac_cv_libhdf5=no])
+        if test "$ac_cv_hadf5_h" = "no" && test "$ac_cv_libhdf5" = "no" ; then
+          AC_MSG_WARN([Unable to compile HDF5 test program])
+        fi
+        dnl Look for HDF5's high level library
+        AC_HAVE_LIBRARY([hdf5_hl], [HDF5_LIBS="-lhdf5_hl $HDF5_LIBS"], [], [])
+
+        CC=$ax_lib_hdf5_save_CC
+        CPPFLAGS=$ax_lib_hdf5_save_CPPFLAGS
+        LIBS=$ax_lib_hdf5_save_LIBS
+        LDFLAGS=$ax_lib_hdf5_save_LDFLAGS
+        AC_LANG_POP([C])
+
+        AC_MSG_CHECKING([for matching HDF5 Fortran wrapper])
+        dnl Presume HDF5 Fortran wrapper is just a name variant from H5CC
+        H5FC=$(eval echo -n $H5CC | $SED -n 's/cc$/fc/p')
+        if test -x "$H5FC"; then
+            AC_MSG_RESULT([$H5FC])
+            with_hdf5_fortran="yes"
+            AC_SUBST([H5FC])
+
+            dnl Again, pry any remaining -Idir/-Ldir from compiler wrapper
+            for arg in `$H5FC -show`
+            do
+              case "$arg" in #(
+                -I*) echo $HDF5_FFLAGS | $GREP -e "$arg" >/dev/null \
+                      || HDF5_FFLAGS="$HDF5_FFLAGS $arg"
+                  ;;#(
+                -L*) echo $HDF5_FFLAGS | $GREP -e "$arg" >/dev/null \
+                      || HDF5_FFLAGS="$HDF5_FFLAGS $arg"
+                     dnl HDF5 installs .mod files in with libraries,
+                     dnl but some compilers need to find them with -I
+                     echo $HDF5_FFLAGS | $GREP -e "-I${arg#-L}" >/dev/null \
+                      || HDF5_FFLAGS="$HDF5_FFLAGS -I${arg#-L}"
+                  ;;
+              esac
+            done
+
+            dnl Make Fortran link line by inserting Fortran libraries
+            for arg in $HDF5_LIBS
+            do
+              case "$arg" in #(
+                -lhdf5_hl) HDF5_FLIBS="$HDF5_FLIBS -lhdf5hl_fortran $arg"
+                  ;; #(
+                -lhdf5)    HDF5_FLIBS="$HDF5_FLIBS -lhdf5_fortran $arg"
+                  ;; #(
+                *) HDF5_FLIBS="$HDF5_FLIBS $arg"
+                  ;;
+              esac
+            done
+        else
+            AC_MSG_RESULT([no])
+            with_hdf5_fortran="no"
+        fi
+
+	AC_SUBST([HDF5_VERSION])
+	AC_SUBST([HDF5_CC])
+	AC_SUBST([HDF5_CFLAGS])
+	AC_SUBST([HDF5_CPPFLAGS])
+	AC_SUBST([HDF5_LDFLAGS])
+	AC_SUBST([HDF5_LIBS])
+	AC_SUBST([HDF5_FC])
+	AC_SUBST([HDF5_FFLAGS])
+	AC_SUBST([HDF5_FLIBS])
+	AC_SUBST([HDF5_TYPE])
+	AC_DEFINE([HAVE_HDF5], [1], [Defined if you have HDF5 support])
+    fi
+fi
+])
diff --git a/pkgconfig/trexio.pc.in b/pkgconfig/trexio.pc.in
index 69484d4..3897402 100644
--- a/pkgconfig/trexio.pc.in
+++ b/pkgconfig/trexio.pc.in
@@ -7,8 +7,9 @@ Name: @PACKAGE_NAME@
 Description: TREX Input/Output library
 URL: https://github.com/trex-coe/trexio
 Version: @PACKAGE_VERSION@
-Cflags:  -I${includedir} @PKG_CFLAGS@
-Libs: -L${libdir} -ltrexio -lm @PKG_LIBS@ 
+Cflags:  -I${includedir}
+Libs: -L${libdir} -ltrexio
+Libs.private: @LIBS@
 Requires: @PKG_HDF5@
 Requires.private: @PKG_HDF5@
 
diff --git a/src/templates_front/templator_front.org b/src/templates_front/templator_front.org
index 1433fc9..f62cb23 100644
--- a/src/templates_front/templator_front.org
+++ b/src/templates_front/templator_front.org
@@ -706,8 +706,7 @@ trexio_exit_code transform_str (char** dest, const char** src, uint64_t str_max_
 
 * Templates for front end
 
-  Consider the following block of ~trex.json~:
-
+  Consider the following block of =trex.json=:
 
    #+begin_src python
   {
@@ -722,7 +721,7 @@ trexio_exit_code transform_str (char** dest, const char** src, uint64_t str_max_
 
   ~TREXIO~ is generated automatically by the ~generator.py~ Python
   script based on the tree-like configuration provided in the
-  ~trex.json~ file.  Because of that, generalized templates can be
+  =trex.json= file.  Because of that, generalized templates can be
   implemented and re-used.  This approach minimizes the number of bugs
   as compared with manual copy-paste-modify scheme.
 
@@ -758,14 +757,14 @@ trexio_exit_code transform_str (char** dest, const char** src, uint64_t str_max_
    construction of TREXIO (e.g. ~num~ of ~nucleus~ group becomes
    ~nucleus_num~ and should be accessed accordingly within TREXIO).
 
-   TREXIO generator parses the ~trex.json~ file. TREXIO operates with
+   TREXIO generator parses the =trex.json= file. TREXIO operates with
    names of variables based on the 1-st (parent group) and 2-nd (child
-   object) levels of ~trex.json~ .  The parsed data is divided in 2
+   object) levels of =trex.json= .  The parsed data is divided in 2
    parts:
 
    1) Dimensioning variables (contain ~num~ in their names). These are always scalar integers.
-   2) Datasets. These can be vectors, matrices or tensors. The types are indicated in ~trex.json~.
-      Currently supported types: int, float. TODO: strings.
+   2) Datasets. These can be vectors, matrices or tensors. The types are indicated in =trex.json=.
+      Currently supported types: int, float and strings.
 
    For each of the aforementioned objects, TREXIO provides *has*,
    *read* and *write* functionality.  TREXIO supports I/O with single
@@ -1402,6 +1401,18 @@ interface
 end interface
      #+end_src
 
+** Sparse data structures
+
+   Sparse data structures are used typically for large tensors such as
+   two-electron integrals. For example, in the =trex.json= file sparse
+   arrays appear as the ~eri~ array:
+
+   #+begin_src python
+   "ao_2e_int"  : {
+     "eri_num"  : [ "int", [  ] ]
+     "eri"      : [ "float sparse", [ "ao.num", "ao.num", "ao.num", "ao.num" ] ]
+   }
+   #+end_src
 * Fortran helper/wrapper functions
 
   The function below adapts the original C-based ~trexio_open~ for Fortran.