diff --git a/lib/node_modules/@stdlib/stats/base/dists/planck/pmf/README.md b/lib/node_modules/@stdlib/stats/base/dists/planck/pmf/README.md
index 3e232251e9fa..24cd9348d62f 100644
--- a/lib/node_modules/@stdlib/stats/base/dists/planck/pmf/README.md
+++ b/lib/node_modules/@stdlib/stats/base/dists/planck/pmf/README.md
@@ -123,6 +123,105 @@ for ( i = 0; i < lambda.length; i++ ) {
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+## C APIs
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+### Usage
+
+```c
+#include "stdlib/stats/base/dists/planck/pmf.h"
+```
+
+#### stdlib_base_dists_planck_pmf( x, lambda )
+
+Evaluates the probability mass function(pmf) of a Planck distribution with shape parameter `lambda`.
+
+```c
+double out = stdlib_base_dists_planck_pmf( 4.0 , 3.0 );
+// returns ~0.0781
+```
+
+The function accepts the following arguments:
+
+- **x**: `[in] double` input value.
+- **lambda**: `[in] double` shape parameter.
+
+```c
+double stdlib_base_dists_planck_pmf( const double x, const double lambda );
+```
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+### Examples
+
+```c
+#include "stdlib/stats/base/dists/planck/pmf.h"
+#include
+#include
+static int random_discrete_uniform( const int min, const int max ) {
+ return min + rand() % ( max - min + 1 );
+}
+
+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 ) {
+ int x;
+ double lambda;
+ double y;
+ int i;
+
+ for ( i = 0; i < 10; i++ ) {
+ x = random_discrete_uniform( 0, 5 );
+ lambda = random_uniform( 0.1, 5.0 );
+ y = stdlib_base_dists_planck_pmf( x, lambda );
+ printf( "x: %d, \u03BB: %lf, P(X = x; \u03BB): %lf\n", x, lambda, y );
+ }
+ return 0;
+}
+```
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