diff --git a/lib/node_modules/@stdlib/stats/base/dists/signrank/pdf/README.md b/lib/node_modules/@stdlib/stats/base/dists/signrank/pdf/README.md
index 00c29246c2eb..eaaaa065a4c1 100644
--- a/lib/node_modules/@stdlib/stats/base/dists/signrank/pdf/README.md
+++ b/lib/node_modules/@stdlib/stats/base/dists/signrank/pdf/README.md
@@ -126,6 +126,103 @@ for ( i = 0; i < 10; i++ ) {
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+## C APIs
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+### Usage
+
+```c
+#include "stdlib/stats/base/dists/signrank/pdf.h"
+```
+
+#### stdlib_base_dists_signrank_pdf( x, n )
+
+Evaluates the probability density function (PDF) of the Wilcoxon signed rank test statistic with `n` observations.
+
+```c
+double out = stdlib_base_dists_signrank_pdf( 7.0, 9 );
+// returns ~0.01
+```
+
+The function accepts the following arguments:
+
+- **x**: `[in] double` input value.
+- **n**: `[in] int32_t` number of observations.
+
+```c
+double stdlib_base_dists_signrank_pdf( const double x, const int32_t n );
+```
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+### Examples
+
+```c
+#include "stdlib/stats/base/dists/signrank/pdf.h"
+#include "stdlib/math/base/special/ceil.h"
+#include
+#include
+#include
+
+static double random_uniform( const double min, const double max ) {
+ double v = (double)rand() / ( (double)RAND_MAX + 1.0 );
+ return min + ( v*(max-min) );
+}
+
+int main( void ) {
+ int32_t n;
+ double x;
+ double y;
+ int i;
+
+ for ( i = 0; i < 25; i++ ) {
+ x = random_uniform( 0, 30.0 );
+ n = (int32_t)stdlib_base_ceil( random_uniform( 1.0, 30.0 ) );
+ y = stdlib_base_dists_signrank_pdf( x, n );
+ printf( "x: %lf, n: %d, f(x;n): %lf\n", x, n, y );
+ }
+}
+```
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